diff --git a/src/lock/api.rs b/src/lock/api.rs
index 3b9b6b1618..e48be61b5a 100644
--- a/src/lock/api.rs
+++ b/src/lock/api.rs
@@ -11,7 +11,7 @@ use core::ops::{Deref, DerefMut};
 // TODO: For weak memory, there needs to be a bit more stricter condition. unlock -hb→ lock.
 pub unsafe trait RawLock: Default + Send + Sync {
     /// Raw lock's token type.
-    type Token;
+    type Token: Send + Sync;
 
     /// Acquires the raw lock.
     fn lock(&self) -> Self::Token;
diff --git a/src/lock/clhlock.rs b/src/lock/clhlock.rs
index c85fb43dfb..9bf850be0a 100644
--- a/src/lock/clhlock.rs
+++ b/src/lock/clhlock.rs
@@ -12,6 +12,9 @@ struct Node {
 #[derive(Debug, Clone)]
 pub struct Token(*const CachePadded<Node>);
 
+unsafe impl Send for Token {}
+unsafe impl Sync for Token {}
+
 /// CLH lock.
 #[derive(Debug)]
 pub struct ClhLock {
diff --git a/src/lock/mcslock.rs b/src/lock/mcslock.rs
index edae4fc164..d7c99916b7 100644
--- a/src/lock/mcslock.rs
+++ b/src/lock/mcslock.rs
@@ -14,6 +14,9 @@ struct Node {
 #[derive(Debug, Clone)]
 pub struct Token(*mut CachePadded<Node>);
 
+unsafe impl Send for Token {}
+unsafe impl Sync for Token {}
+
 /// An MCS lock.
 #[derive(Debug)]
 pub struct McsLock {
diff --git a/src/lock/mcsparkinglock.rs b/src/lock/mcsparkinglock.rs
index 4aab2b931a..5e6dc67387 100644
--- a/src/lock/mcsparkinglock.rs
+++ b/src/lock/mcsparkinglock.rs
@@ -16,6 +16,9 @@ struct Node {
 #[derive(Debug, Clone)]
 pub struct Token(*mut CachePadded<Node>);
 
+unsafe impl Send for Token {}
+unsafe impl Sync for Token {}
+
 /// An MCS parking lock.
 #[derive(Debug)]
 pub struct McsParkingLock {