A saddle riding vehicle includes a storage box and an anti-theft system. The storage box is openable in a vehicle horizontal direction. The anti-theft system is configured to measure position information on the vehicle and to send the position information via radio, the anti-theft system being attached to an undersurface of a ceiling of the storage box. Preferably, the anti-theft system is rotatably attached to the undersurface of the ceiling of the storage box by a hinge and the anti-theft system is attached to the tray member.