Hydrostatic stepless transmission

A hydrostatic stepless transmission joined to a transmission housing includes a hydraulic pump, a hydraulic motor, a port block and a charge pump. The port block includes first and second side surfaces opposite each other. The hydraulic pump and motor are mounted on the first side surface of the port block so as to be fluidly connected to each other via a hydraulic circuit formed in the port block. The charge pump includes a pump housing mounted to the second side surface of the port block. The pump housing includes a mount part to which the transmission housing is mounted.