To provide a toothbrush vibrating device which is suitable for preventing gum disease and which can vibrate a toothbrush while maintaining storability and portability as good as those of toothbrushes on the market.

The toothbrush vibrating device 1 includes a C-shaped member 2, flat vibrating motors 3 and 3 provided on the outer peripheral surface 23 of the member, a battery holder 4, and a switch 5. The vibrating device 1 is inserted from the neck part 72 of the toothbrush 7 and slid toward a grip region 73 so as to be fixed to a grip front part 732.