A motorcycle includes a rear arm, at one end of which a rear wheel is axially supported and the other end of which is pivotally supported by a body frame via a pivotally supporting shaft. A spring unit is interposed between the rear arm and the body frame so as to be located between the pivotally supporting shaft and the rear wheel. A lock arm placing section houses a lock arm for theft prevention having left and right arm sections and a bent section coupling ends of the left and right arm sections to each other. The lock arm placing section houses the lock arm in a position in which the left and right arm sections of the lock arm are located on both sides of the spring unit.