Provided is an image acquisition device for dental handpiece capable of acquiring a clear image even though cooling water is supplied. An image acquisition device (11) detachable to a dental handpiece body (1), the device including a light inlet part having a light acquisition port capable of acquiring light, a holding member (14, 15) holding the light inlet part to the dental handpiece body, wherein the light acquisition port can be held to the dental handpiece body by means of the holding member in such a manner that it can be shifted to a side which is away from an instrument than a plane of an instrument-mounting surface of a head (2) of the dental handpiece body and in a region outside of an outer peripheral surface of the head.