"Ai no shirushi" is the 6th single released by Japanese pop duo Puffy AmiYumi.

This song was written and composed by Masamune Kusano of band Spitz.

They also sang a Chinese Mandarin version of it on their album The Very Best of Puffy/AmiYumi Jet Fever.

This song was also featured on the live action movie Lovely Complex.

A portion of the song was also featured in the Hi Hi Puffy AmiYumi episode "The Phantom of Rock."