A throttle device which prevents the entry of foreign compounds into a slidable contact portion between a brush and a commutator is provided to prevent the malfunctioning of a motor. A first shielding portion is integrally formed in a brush holder, which is attached to a yoke of a motor for holding a brush. The plate-shaped first shielding portion covers the vicinity of the yoke in the outer periphery of the yoke. Accordingly, the first shielding portion covers a gap left between the yoke and the brush holder, and a slidable contact portion between a commutator and the brush on a throttle gear side. Therefore, the first shielding portion prevents a foreign compound, generated in an engagement portion between the throttle gear and a reduction gear and falling onto a motor, from moving to the slidable contact portion, so that it is possible to prevent poor contact between the commutator and the brush.