PROBLEM TO BE SOLVED: To provide an electric toothbrush equipped with a plaque detection function without increasing the size, weight and manufacturing cost of a main body. An electric toothbrush 1A has a main body 2 incorporating a drive motor 11 and a control unit 12, a replacement brush 5 that can be attached to the main body and is driven by the drive motor, and a plaque detection unit that can be attached to the main body. The main body has a main body side connection portion 2B for connection with the plaque detection unit, and the plaque detection unit emits excitation light that excites a fluorescent substance contained in the plaque. The control unit has a fluorescence detection module 20 that receives fluorescence generated by teeth irradiated with excitation light and a unit-side connection unit 3B that is connected to the main body-side connection portion, and the control unit has a main body-side connection portion and a unit side. Either the drive motor or the fluorescence detection module is operated based on the presence or absence of the connection with the connection portion. [Selection diagram] Fig. 2【課題】本体のサイズ、重量および製造コストを増大させずに歯垢検出機能を搭載する電動歯ブラシを提供する。【解決手段】電動歯ブラシ１Ａは、駆動モータ１１および制御部１２を内蔵する本体２と、本体に装着可能であり、駆動モータにより駆動される交換ブラシ５と、本体に装着可能な歯垢検出ユニット３とを有し、本体は、歯垢検出ユニットとの接続のための本体側接続部２Ｂを有し、歯垢検出ユニットは、歯垢に含まれる蛍光物質を励起する励起光を出射するとともに、励起光が照射された歯で生じた蛍光を受光する蛍光検出モジュール２０と、本体側接続部に接続されるユニット側接続部３Ｂとを有し、制御部は、本体側接続部とユニット側接続部との接続の有無に基づいて、駆動モータと蛍光検出モジュールとのいずれかを動作させる。【選択図】図２
