<；P>；PROBLEM TO BE SOLVED: To provide a riding lawn mower improved in convenience when the mower is on an inclined surface. <；P>；SOLUTION: A riding lawn mower includes left and right main driving wheels 12, 14, right and left caster wheels 22, 24 as steering control wheels, and controllers 44, 46, 48. At least two main driving wheels 12, 14 are driven by a first electric motor 16 and a second electric motor 18. The controllers 44, 46, 48 have changing modules as changing means. The changing modules perform the changing between a forcible steering mode in which the caster wheels 22, 24 are forcibly steered by electric motors for steering, and a free steering mode in which the generation of the power of the electric motors for steering is stopped, the transmission of the power for steering from the electric motors for steering to the caster wheels 22, 24 is cut off, and the caster wheels 22, 24 are freely steered. <；P>；COPYRIGHT: (C)2008,JPO&INPIT
