Abstract: In a seat drive device that is built in a seat including a central portion and a side support located outside the central portion in a width direction, and drives the side support, the seat drive device includes a base fixed to the seat, a paddle that is rotatably supported with respect to the base and rotates in a unfolding direction to displace the side support toward a seating region of a user, and an air bag that is disposed between the base and the paddle and rotates the paddle in the unfolding direction by expansion accompanying air supply, wherein the paddle includes a pressing portion that presses the side support from inside, and an arm that is rotatably supported with respect to the base and extends toward the pressing portion, wherein a rotation axis of the paddle is located at the central portion of the seat, and wherein the arm is curved toward a retraction direction that is a direction opposite to the unfolding direction.

Abstract: In a seat drive device that is built in a seat including a central portion and a side support located outside the central portion in a width direction, and drives the side support, the seat drive device includes a base fixed to the seat, a paddle that is rotatably supported with respect to the base and rotates in a unfolding direction to displace the side support toward a seating region of a user, and an air bag that is disposed between the base and the paddle and rotates the paddle in the unfolding direction by expansion accompanying air supply, wherein the paddle includes a pressing portion that presses the side support from inside, and an arm that is rotatably supported with respect to the base and extends toward the pressing portion, wherein a rotation axis of the paddle is located at the central portion of the seat, and wherein the arm is curved toward a retraction direction that is a direction opposite to the unfolding direction.