diff --git a/CHANGELOG.md b/CHANGELOG.md
index 90bdc77..2ca3bf2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 ## Packaging
 
+# v3.0.3
+
+https://github.com/proshunsuke/colmsg/pull/88
+
+## Fix
+
+* Use [rayon](https://crates.io/crates/rayon) to speed up internal processing
+
 # v3.0.2
 
 https://github.com/proshunsuke/colmsg/pull/86
diff --git a/Cargo.lock b/Cargo.lock
index c2ab0a9..a785d7a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -212,7 +212,7 @@ dependencies = [
 
 [[package]]
 name = "colmsg"
-version = "3.0.2"
+version = "3.0.3"
 dependencies = [
  "ansi_colours",
  "ansi_term",
@@ -226,6 +226,7 @@ dependencies = [
  "lazy_static",
  "liquid",
  "rand 0.7.3",
+ "rayon",
  "regex",
  "reqwest",
  "serde",
@@ -288,6 +289,49 @@ dependencies = [
  "cfg-if 1.0.0",
 ]
 
+[[package]]
+name = "crossbeam-channel"
+version = "0.5.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c2dd04ddaf88237dc3b8d8f9a3c1004b506b54b3313403944054d23c0870c521"
+dependencies = [
+ "cfg-if 1.0.0",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "715e8152b692bba2d374b53d4875445368fdf21a94751410af607a5ac677d1fc"
+dependencies = [
+ "cfg-if 1.0.0",
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "01a9af1f4c2ef74bb8aa1f7e19706bc72d03598c8a570bb5de72243c7a9d9d5a"
+dependencies = [
+ "autocfg",
+ "cfg-if 1.0.0",
+ "crossbeam-utils",
+ "memoffset",
+ "scopeguard",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fb766fa798726286dbbb842f174001dab8abc7b627a1dd86e0b7222a95d929f"
+dependencies = [
+ "cfg-if 1.0.0",
+]
+
 [[package]]
 name = "crypto-common"
 version = "0.1.6"
@@ -938,6 +982,15 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
 
+[[package]]
+name = "memoffset"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5de893c32cde5f383baa4c04c5d6dbdd735cfd4a794b0debdb2bb1b421da5ff4"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "mime"
 version = "0.3.16"
@@ -1402,6 +1455,28 @@ dependencies = [
  "rand_core 0.5.1",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db3a213adf02b3bcfd2d3846bb41cb22857d131789e01df434fb7e7bc0759b7"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cac410af5d00ab6884528b4ab69d1e8e146e8d471201800fa1b4524126de6ad3"
+dependencies = [
+ "crossbeam-channel",
+ "crossbeam-deque",
+ "crossbeam-utils",
+ "num_cpus",
+]
+
 [[package]]
 name = "rdrand"
 version = "0.4.0"
@@ -1528,6 +1603,12 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
+
 [[package]]
 name = "scratch"
 version = "1.0.2"
diff --git a/Cargo.toml b/Cargo.toml
index 2fd7e57..b43399f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "colmsg"
-version = "3.0.2"
+version = "3.0.3"
 authors = ["proshunsuke <shunsuke0901@gmail.com>"]
 categories = ["command-line-utilities"]
 description="Save the messages of '櫻坂46メッセージ', '日向坂46メッセージ' and '乃木坂46メッセージ' apps to the local."
@@ -25,6 +25,7 @@ shell-words = "^0.1.0"
 chrono = "^0.4.10"
 serde_json = "^1.0.0"
 walkdir = "^2.3.1"
+rayon = "^1.6.1"
 regex = "^1.3.5"
 url = "^2.1.1"
 
diff --git a/src/message/saver.rs b/src/message/saver.rs
index ef8f41b..13d750c 100644
--- a/src/message/saver.rs
+++ b/src/message/saver.rs
@@ -1,6 +1,7 @@
 use std::fs;
 use std::path::{PathBuf};
 
+use rayon::prelude::*;
 use regex::Regex;
 use walkdir::{WalkDir, DirEntry};
 use chrono::NaiveDateTime;
@@ -11,6 +12,10 @@ use crate::{
     message::file::{Text, Picture, SaveToFile, Video, Voice},
 };
 
+lazy_static! {
+    static ref ID_DATE_REGEX: Regex = Regex::new(r"(?x)(?P<id>\d+)_\d_(?P<date>\d+)").unwrap();
+}
+
 pub struct Saver<'a, C: SHNClient> {
     config: &'a Config<'a, C>,
 }
@@ -46,7 +51,7 @@ impl<'b, C: SHNClient> Saver<'b, C> {
     }
 
     fn create_member_identifier_list(&self, group: &Vec<Groups>, tags: &Vec<Tags>) -> Vec<MemberIdentifier> {
-        let mut member_identifier_vec = Vec::new();
+        let mut member_identifier_vec = Vec::with_capacity(group.len());
         group.iter().for_each(|g| { // もっといい書き方があるはず
             let mut group = "".to_string();
             let mut gen = "".to_string();
@@ -175,6 +180,7 @@ impl<'b, C: SHNClient> Saver<'b, C> {
     fn id_dates(&self, dir_buf: &PathBuf) -> Vec<IdDate> {
         let mut result = WalkDir::new(dir_buf)
             .into_iter()
+            .par_bridge()
             .filter(|r| !r.as_ref().unwrap().path().is_dir())
             .map(|r| {
                 let dir_entry = r.unwrap();
@@ -215,7 +221,7 @@ struct IdDate {
 }
 
 fn dir_entry_to_id_date(filename: &DirEntry) -> Option<IdDate> {
-    let re = Regex::new(r"(?x)(?P<id>\d+)_\d_(?P<date>\d+)").unwrap();
+    let re = ID_DATE_REGEX.clone();
     re.captures(filename.file_name().to_str().unwrap())
         .and_then(|cap|Some(IdDate {
             id: cap["id"].parse::<u32>().unwrap(),