A self-propelled mower includes a mover main body a battery, an electric generator, or an engine a protruding wing that protrudes sideward, the protruding wing being retractable and an extension length of the protruding wing being variable mowing units protruding from a front face of the mover main body and a front face of the protruding wing, each including a movable blade that reciprocates or rotates to cut grasses driven by an electric motor or the engine, the electric motor being powered by battery or the electric generator. The mover main body moves on a slope face while being towed, via a traction rope, by a straddle-type mover body that moves straddling on a guard rail installed on top of a slope of a bank or moves on the ground or in the air while being suspended by a suspension rope hung from a spanning cable spanning in the air.
