PROBLEM TO BE SOLVED: To provide a technique reasonably switching the blade-driving mode of a lawn mower between a both blade-driving mode and a single blade-driving mode.SOLUTION: This lawn mower has a driving mode-switching member 157 for switching a driving mode between a both blade-driving mode for driving an upper blade 152 and a lower blade 153 and a single blade-driving mode for driving the upper blade and inhibiting the driving of the lower blade. When the driving mode-switching member 157 is placed on the lower side of a base plate 154, the mounting height position with respect to the blade-mounting portion of a blade assembly is switched to an upper position. Thus, the engagement state of an upper blade-driving member 133 with the upper blade and the engagement state of a lower blade-driving member 135 with the lower blade are maintained, respectively, and the upper blade and the lower blade can be driven. When the driving mode-switching member 157 is placed on the upper side of the base plate 154, the mounting vertical height position with respect to the blade-mounting portion of the blade assembly is switched to a lower position to maintain the engagement state of the upper blade-driving member 133 with the upper blade. Thus, the engagement state of the lower blade-driving member 135 with the lower blade is disengaged, and only the upper blade can be driven.COPYRIGHT: (C)2007,JPO&INPIT【課題】 芝刈り機の刃物の駆動モードを両刃駆動モードと片刃駆動モードとの間で合理的に切り替えられる技術を提供する。【解決手段】芝刈り機は、上刃152と下刃153を駆動する両刃駆動モードと、上刃を駆動し、下刃の駆動を禁止する片刃駆動モードとの間で切替る駆動モード切替部材157を有する。駆動モード切替部材がベース板154の下面のときには、刃物アッセンブリーの刃物装着部に対する装着高さ位置が上方位置へと切り替えられて上刃駆動部材133と上刃との係合状態と下刃駆動部材135と下刃との係合状態がそれぞれ維持され、上刃と下刃が駆動可能とされ、駆動モード切替部材がベース板の上面のときには、刃物アッセンブリーの刃物装着部に対する上下方向の装着高さ位置が下方位置へと切替られて上刃駆動部材と上刃との係合状態が維持されて、下刃駆動部材と下刃との係合が解除され、上刃のみが駆動可能とされる。【選択図】 図6
