Abstract: This application relates to a wheel steering angle adjustment device for a vehicle operated by manpower. The device may include a fixed body including a rotation support, a rotation body, a lift member coupled to the rotation support, a locking switch coupled to the lift member, and a plurality of fixing groove portions in the outer peripheral surface of the rotation support. The device may also include a fixing protrusion protruding from the locking switch and configured to be detachably coupled to the fixing groove portions, a rotation range limiting stopper provided on a lower portion of the lift member, and a rotation guide groove portion provided concavely in an upper surface of the rotation body. As the rotation range limiting stopper becomes stuck on an end portion of the rotation guide groove portion, an angle by which the rotation body is rotatable relative to the fixed body is limited.