A transmission comprises a casing, an output element, a hydrostatic stepless transmission unit (HST) and a forward/backward traveling direction selecting unit (reverser). The output element is supported by the casing. The HST is disposed in the casing so as to be driven by a drive source disposed outside of the casing. The HST includes a pump shaft and a motor shaft member. The pump shaft is drivingly connected to the drive source. The motor shaft member is fitted around the pump shaft coaxially to the pump shaft so as to be rotatable relative to the pump shaft, thereby constituting a hydraulic pump and a hydraulic motor centered on the pump shaft and the motor shaft member. An axially distal end of the motor shaft member is disposed on the axially proximal side of an axially distal end of the pump shaft so that axial ends of the pump shaft are the axially most distal ends of the HST in the axial direction of the pump shaft. The reverser is disposed in the casing so as to transmit power outputted from the HST to the output element. The reverser includes a forward-traveling drive train, a backward-traveling drive train, and a clutch for selecting either the forward-traveling drive train or the backward traveling drive train to transmit the power outputted from the motor shaft member to the output element. The reverser and the output element are entirely disposed between the axial ends of the pump shaft in the axial direction of the pump shaft.