A wheelchair has actuation plates provided in juxtaposition with the seat to descend when a user sits on the seat to lower the seat with the weight and to ascend when the user rises from the seat to permit the seat to return with removal of the weight, brake means mounted on the axle shafts to brake the axle shafts and energized constantly in a non-braking direction, and levers coupled directly or indirectly to the brake means to move according to descending motions of the actuation plates to act on the brake means to put the brake means in a non-braking state and to move according to ascending motions of the actuation plates to act on the brake means to put the brake means in a braking state.