US Patent 10227106 Bicycle controller and bicycle drive device

A bicycle controller and bicycle drive device that improves the stability of the behavior of a bicycle. The bicycle controller includes an electronic control unit that reduces the output of a motor, which is configured to assist in propulsion of the bicycle, in accordance with an angular acceleration of a rotary body. The rotary body is included in a human power transmission path extending from an input for human power to a coupling portion coupled to a drive wheel.