A bar handle 5 is provided to extend from the rear parts of right and
left
side frames 3 and to form a gate shape in a double member structure made
up of a fixed member 32 attached to the rear parts of the right and left
side frames 3 and a movable member 33 disposed along at least upper
side portion of the fixed member 33. A displacement detecting means 42
is interposed between the fixed member 32 and the movable member 33
to detect displacement of the movable member 33 relative to the fixed
member 32. A control means is provided to control a driving motor so as
to produce assisting power commensurate with the detected displacement.
