A bicycle drive unit is basically provided with an input rotational shaft, an output part, a transmission mechanism, an assist motor and a switching mechanism. The transmission mechanism has at least two shift stages, and is configured to change a speed of a rotational input that is input from the input rotational shaft and output this rotational input to the output part. The assist motor is coupled to a power transmission path from the input rotational shaft to the output part, and is driven according to a manual drive force. The switching mechanism is configured to switch a gear changing state of the transmission mechanism by using a rotational force of the assist motor.