A lawn mower includes a grass discharge passage extending rearward from a housing 11. A grass receptacle is removably mounted to the discharge passage via a receptacle mounted portion. A shutter is provided at a passage opening of the grass discharge passage facing the housing. The shutter is rotatably provided within the housing to adjust the degree of opening of the passage opening. The lawn mower is switched between a bagging mode, a mulching mode and an intermediate mode by the opening control with the shutter.