A rear-engine type riding lawn tractor having a frame, an engine carried on the frame, a cutting mower driven the engine, a seat set on the frame, a caster wheel supported on the front frame, a pair of drive wheels supported on the rear frame, axles connected with the pair of drive wheels, a HST for drive and a HST for steering included in the transmission, a transmission case arranged on the left and right direction in the frame, a drive belt transmitting power to the cutting mower from the engine over the axle.