심장소리

김건우

Cheol-yi

Jeon Do-yeon

Cheol-yi's Mother

Sul Kyung-gu

Cheol-yi's Father

강주리

Teacher

이한별

Kid

김수현

Kid

서지호

Kid

김예성

Kid

Song Won-su

Elder

Lee Joong-ok

Police Officer

Kim Hak-sun

Vest

Park Ok-chool

Neighbor's child's mother