A lawn mower comprises a blade drive shaft with a blade rotatably mounted inside a mower deck supported by a vehicle body, a blower unit including a cylindrical blower housing connected to a grass clippings discharging section provided in a side end region of the mower deck, a vertical drive shaft having a shaft portion with vanes attached thereto inside the blower housing and a shaft portion extending upward through the blower housing, and a discharging sleeve projecting rearwardly along an outer tangent line of the blower housing, a grass collecting apparatus mounted rearwardly of the vehicle body, a duct for allowing the discharging sleeve to communicate with the grass collecting apparatus, and a belt-type blower driving mechanism for driving the vertical drive shaft of the blower unit. The belt-type blower driving mechanism includes an intermediate vertical shaft disposed rearwardly of the blower housing, and a belt transmission unit for transmitting power from the blade drive shaft to the vertical drive shaft through the intermediate vertical shaft.