diff --git a/src/Action.php b/src/Action.php
index 3396891..b7aee6c 100644
--- a/src/Action.php
+++ b/src/Action.php
@@ -1,6 +1,20 @@
 <?php
+
 namespace Teto\Routing;
 
+use function array_diff;
+use function array_fill_keys;
+use function array_filter;
+use function array_keys;
+use function array_values;
+use function count;
+use function explode;
+use function in_array;
+use function preg_match;
+use function strlen;
+use function strpos;
+use function substr;
+
 /**
  * Action object
  *
diff --git a/src/CommonPrefixTrieRouter.php b/src/CommonPrefixTrieRouter.php
index dfd0c42..0ba4916 100644
--- a/src/CommonPrefixTrieRouter.php
+++ b/src/CommonPrefixTrieRouter.php
@@ -2,6 +2,11 @@
 
 namespace Teto\Routing;
 
+use function ord;
+use function strlen;
+use function substr;
+use function sprintf;
+
 /**
  * 共通接頭辞木構造を連想配列で実装したRouter
  *
diff --git a/src/Router.php b/src/Router.php
index b58aec5..d07e243 100644
--- a/src/Router.php
+++ b/src/Router.php
@@ -2,6 +2,15 @@
 
 namespace Teto\Routing;
 
+use function array_filter;
+use function array_shift;
+use function array_values;
+use function count;
+use function explode;
+use function implode;
+use function is_numeric;
+use function strpos;
+
 /**
  * Router
  *