Provided is a seat having improved rigidity. The seat includes: a first side frame; a second side frame, a connection body; a base member; a first drive-side link; a second drive-side link, an actuator that generates a force for changing an angle between the first drive-side link and the second drive-side link; a first driven-side link that is fixed on the second side frame side of the connection body and rotates integrally with the connection body; a second driven-side link whose first end side is rotatably connected to a second end side of the first driven-side link and whose second end side is rotatably connected to a base member; and a transmission mechanism that mechanically transmits, when a force for rotating the second driven-side link about a connection part between the second driven-side link and the base member acts on the second driven-side link, the force to the connection body.

A seat adjustment device may have a first lead screw, a second lead screw, and a connector. A first portion of the connector may comprise threads that may be adapted to receive threads from the first lead screw. A second portion of the connector may comprise threads that are adapted to receive threads from the second lead screw.