A transmission apparatus of an all-terrain vehicle includes: a non-stage
transmission; a forward and backward movement switching device capable of
switching to a forward movement position, a neutral position, or a
backward movement position; and a shift operation device of rotary type
for switching forward and backward movement disposed on a handle bar at a
position adjacent to a handle grip. The shift operation device includes a
rotary member for a shift operation and a locking mechanism for locking
the rotary member so as not to move toward at least a position for
backward movement from a position for neutral. The locking mechanism is
configured to be handled by a hand griping the handle grip to make the
locking mechanism unlocked.