A seat device for a vehicle includes: a support member detachably attached to a floor of the vehicle; an occupant seat movably supported by the support member and provided with an electrical component; and a wireless power supply mechanism configured to supply electric power to the electrical component. The wireless power supply mechanism includes a power transmitting unit attached to the floor, and a power receiving unit attached to the support member so as to face the power transmitting unit and configured to receive the electric power wirelessly from the power transmitting unit.