A lawn mower (10) includes a drive source (15) for driving a cutter blade (14) through a rotation shaft (41), a flap (52) provided for the cutter blade (14) in a manner that the flaps (52) have a flap angle (¸r) changeable along a horizontal line (46) which is perpendicular to the rotation shaft (41), an actuator (60) for controlling the flap angle (¸r) of the flaps (52), a control unit (117) for controlling the actuator (60), and a blade switching unit (104) for switching the cutter blade (14) between an operation state and a stop state. When the control unit (117) determines that a stop switch signal has been received from the blade switching unit (104), the control unit (117) controls the actuator (60) to increase the flap angle (¸r) of the flaps (52).
