Riding lawn mower

A riding lawn mower comprising:

• a housing opening downward and having a cutting blade accommodated therein;
• a cut grass receptacle disposed rearward of the housing;
• a cut grass delivery passage for delivering grass, cut by the cutting blade, from the housing to the cut grass receptacle;
• and
• a shutter mechanism provided on a lower portion of the cut grass delivery passage for switching the lawn mower between a bagging mode in which grass cut by the cutting blade is delivered from the housing to the cut grass receptacle and a mulching mode in which grass cut by the cutting blade is discharged downward of the housing,
• the shutter mechanism comprising a base mounted on a lower portion of the cut grass delivery passage, a horizontal pivot shaft disposed on the lower portion of the cut grass delivery passage, and a shutter plate pivotable about the pivot shaft between a fully closed position where the shutter plate closes the cut grass delivery passage in order to execute the mulching mode and a fully opened position where the shutter plate is laid down toward a discharge side of the cut grass delivery passage in order to execute the bagging mode, and
• an operating force transmission section for transmitting opening/closing operation force, given via an operation section being disposed away from the shutter mechanism, to the shutter plate,
• wherein the operation section is configured to switch the shutter plate between the fully closed position and the fully opened position,
• wherein in the fully opened position of the cut grass delivery passage, the shutter plate is laid down toward a discharge side of the cut grass delivery passage, and
• wherein the shutter mechanism is constructed as a single unit integrally including:
• the base, the pivot shaft and the shutter plate assembled to the base, and the operating force transmission section, the single unit detachably attached to the cut grass delivery passage.