The thickness of the thin bidirectional ratchet wrench of the present disclosure is preferably less than or equal to 30.0 mm, it can be used in narrow spaces easily, achieves two working modes, and can convert between them conveniently and stably. During use of the thin bidirectional ratchet wrench of the present disclosure, the input torque that the operator exerts is a clockwise torque or a counterclockwise torque, the output torque of the output end of the thin bidirectional ratchet wrench of the present disclosure is a clockwise torque or a counterclockwise torque, alternatively.