A seating posture is stabilized for the shoulders of a passenger seated on a vehicle seat. A vehicle seat is provided with a seat back configured to support the seated person from the rear. A shoulder support portion of the seat back configured to support a corresponding one of the shoulders of the seated passenger includes an air cell configured to expand when air is supplied. When the air cell expands, one end portion of the shoulder support portion on the outside in the width direction of the vehicle seat moves more forward than the other end portion of the shoulder support portion on the inside in the width direction.