Seated position is stabilized by properly holding the shoulder of a person sitting in a vehicle seat. A vehicle seat (S) is provided with a seat back (S1) that supports a sitting person from the back. A shoulder support portion (Sa1) of the seat back (S1) that supports the shoulder of the sitting person includes an air cell (10) that is expanded when charged with air. When the air cell (10) is expanded, one end of the shoulder support portion (Sa1) that is on the outer side in a width direction of the vehicle seat (S) is moved more toward the front than another end on the inner side in the width direction.