The present invention provides a wireless transmission unit for use in a dental instrument with a built-in camera, which is capable of wirelessly transmitting camera images to various destination apparatuses and achieving an improvement in visibility of an affected part while improving operability for a dentist or the like during treatment, and the promotion of patient understanding of the contents of treatment.A wireless transmission unit (51) of the present invention is configured to have a mounting cylinder (55) having a cylindrical connector section (53) which is fitted on an outer periphery of a hand piece main section (2) of a camera built-in hand piece (1) which is a dental instrument with a built-in camera, and in which the other end of a connection wiring part having one end connected to a built-in camera unit (31) is led outside the hand piece main section (2) so that the cylindrical connector section is connected to the other end and an image processing wireless transmission means (58) which has a linking connector part (56) linked to the cylindrical connector section (53) and is detachably coupled at an outer peripheral portion of the hand piece main section (2) by connector liking with the mounting cylinder (55), and which captures an image signal of a target location picked up by the camera unit (31) from the linking connector part (56) through the connection wiring part and the cylindrical connector section (53), performs image processing on the captured image signal of the target location, and wirelessly transmits the same to destination apparatuses as target-location image information.
