PURPOSE: To improve rigidity and increase the effect of robbery prevention, by extending a lock bar guide portion guiding the projection/recession of a lock bar, to the lock hole of a head pipe, and supporting it at the inner periphery of the lock hole, and at the same time supporting it also by means of a fitting plate.

CONSTITUTION: At a scooter, a steering shaft 20 at whose upper end a handle 12 is fixed, is turnably supported at a head pipe 17 at the front end of a scooter body frame 14, and a steering lock device 21 is provided at this head pipe 17. This lock device 21 makes a lock bar 30 engaged with and disengaged from a steering shaft 20 lock hole 32 through a drive cam by rotating a key rotor through the insertion of a key into a key hole. In this instance, an extension portion 37 extending from the fitting surface 34 of a cylinder body 22 to the lock hole 35 of the head pipe 17, is formed at a lock bar guide portion 31 which guides slidingly the lock bar 30 and which is integral with the cylinder body 22, and this extension portion 37 is also put on a through-hole 36 provided at a fitting plate 33.