Abstract: A transmission casing, comprising a front casing and a rear casing, houses a transmission, comprising an input shaft whereto power is transmitted from an engine; a pair of axles whereto left and right running wheels of a vehicle are affixed; a running speed changing unit interlocking the pair of axles and the input shaft; a mid-PTO shaft to drive a working machine attached to a belly portion of the working vehicle; and a mid-PTO drive train interlocking the mid-PTO shaft and the input shaft. A PTO clutch mechanism is provided around a PTO transmission shaft so as to provide a condition where only the mid-PTO shaft is driven, a condition where only the rear-PTO shaft is driven, a condition where both PTO shafts are driven and a neutral condition where neither PTO shaft is driven. A brake unit is provided in the mid-PTO drive train to stop the mid-PTO shaft.