To provide a mid-mower type riding lawn mower in which a mower is arranged between front wheels and rear wheels and also power can be easily transmitted to the mower from an engine at the front of a vehicle body, with the height of the vehicle body kept low, the lawn mower is comprised with (a) an engine output shaft 3 arranged at the back of an engine 27 arranged at the front of a vehicle body 1, (b) a first drive shaft 6a arranged diagonally rearward, viewed from the above, toward the back of the vehicle body from the engine output shaft 3, (b) a second drive shaft 6b arranged along the side of a duct 22 at the rear end of the first drive shaft, (c) a third drive shaft 11a to which power is transmitted via a pulley and (d) a belt 12 arranged in a direction parallel to the second drive shaft 6b, and (e) a fourth drive shaft 11b for transmitting power to gears 54 arranged at the front end of the third drive shaft 11a wherein the first drive shaft 6a and the fourth drive shaft 11b are arranged with the rear end being narrower than the front end, viewed from above.
