A method of controlling an ABS unit is provided for controlling a braking force of a bicycle. The method includes determining whether a vehicle speed is greater than or equal to a prescribed speed, and then determining whether the bicycle is in a prescribed state. The prescribed state is at least one of a first state and a second state. The first state is a state in which a difference between a rotational speed of the front wheel and a rotational speed of the rear wheel is greater than or equal to a prescribed rotational speed. The second state is a state in which a change in the rotational speeds of the front and rear wheels is greater than or equal to a prescribed value. The method further includes controlling the ABS unit upon based on the vehicle speed and the prescribed state.