A compound bicycle exercising device includes two foot pedals rotatably attached to a base, for being operated by users, two handle stems pivotally attached to the base, for being rotated by the users, and two rotary members secured to each handle stem. A spindle is rotatably supported on the base, and includes two followers rotatably attached to each end with unidirectional bearings. Two coupling members couple the rotary members to the followers, and a rotary element is engaged between one of the rotary members and one of the followers, to allow the spindle to be rotated in different direction relative to the rotary member, and to allow the spindle to be continuously driven by the handle stems via the followers and the rotary members alternatively, when the handle stems are rotated relative to the pivot axle in reciprocating action.