A seat includes a support base, an unlock member and a lock member. The support base has at least one through hole. The unlock member is movably disposed on the support base and has at least one first driving portion. The lock member is movably disposed on the unlock member. The lock member has at least one lock portion protruding from a surface of the support base through the at least one through hole and at least one second driving portion abutting against the at least one first driving portion. When the unlock member is forced in a first direction to move, the at least one lock portion is forced to move along the at least one first driving portion through the at least one second driving portion and retracts into the support base in a second direction different from the first direction.