A bicycle control device that easily maintains the ratio of the assist force generated by a motor to the human drive force input to a bicycle at a predetermined ratio includes an electronic controller that controls a transmission, which is configured to change the transmission ratio of the bicycle, and the motor, which assists propulsion of the bicycle. The electronic controller is configured to control the motor so that the ratio of the assist force generated by the motor to the human drive force inputted to the bicycle becomes equal to the predetermined ratio. The electronic controller is configured to control the transmission in correspondence with at least one of the output torque of the motor and the human drive force to maintain the predetermined ratio.