Seat structure

A seat structure capable of dealing with both a normal posture and a resting posture and providing sufficient relaxation in the resting posture while ensuring excellent comfortableness of an occupant.According to the present invention, a back frame itself is fixed to a frame support but a cushion frame shifts from a first position A to a second position B according to an occupant's movement and an inclination angle of a pelvis support increases accordingly. The occupant's pelvis portion and a portion lower than the pelvis portion is moved forward but a part of his or her back above his or her breast is not varied. With this structure, the same effect of the resting posture, that is, the posture in which the back frame is reclined in a conventional seat structure, can be obtained. Since the back is not tilted backward, a leg room (footrest) space in a rear seat is not limited.