A mouse adjusting device of a mouse used to adjust the height of a sensing module of the mouse includes a slidable base, a sensor carrier, and an adjusting element. The moving base is movably disposed in the mouse. The bottom portion of the slidable base has at least a ramp portion. The sensor carrier is disposed in the mouse and below the slidable base. The sensor carrier with the sensing module is liftable and lowerable in the mouse. The top portion of the sensor carrier has at least a block portion abutting against the ramp portion of the slidable base. The adjusting element has a drive screw and a drive nut. The drive nut is embedded in the slidable base. An end of the drive screw is rotatably bolted to the drive nut, and another end of the driving screw is rotatably exposed outside the mouse.