A regulation control device comprises an encoder mechanism and a shell set. The encoder mechanism includes a base, a PCB, and an encoder, the PCB being arranged on a side of the substrate and a fixed shaft on an opposite side of the PCB being arranged in the base. The encoder connects the base and electrically connects the PCB. The shell set includes a press shell, a connecting seat, a rotating seat, and a supporter, the press shell being at a side of the base, the connecting seat being on the other side of the base, connecting the encoder, and being in the rotating seat connecting the connecting seat so that the connecting seat and the rotating seat can be rotatably assembled with the encoder. With the encoder mechanism, the device may provide a better effect of repeated clockwise/counter-clockwise rotation at the angle of 360.