Electric toothbrush

An electric toothbrush comprising:

• an outer case including a handle part, and a head part extending from the handle part and having an opening area open to front;
• first and second electrodes disposed in the opening area and providing electromagnetic waves corresponding to a driving signal;
• and
• a head cover having a plurality of bristle holes, a first electrode hole, and a second electrode hole, which are formed therein, and closing the opening area,
• wherein the first and second electrodes penetrate the first and second electrode holes, respectively, and are exposed to outside,
• the electric toothbrush further comprising:
• a main substrate on which a signal supply unit for generating the driving signal is mounted, the main substrate being accommodated in the handle part;
• and
• a sub-substrate elongated from the main substrate toward the head part and having an end portion positioned within the opening area,
• wherein a first substrate hole and a second substrate hole are formed at the end portion of the sub-substrate, and
• wherein the first electrode is inserted into and fixed to the first substrate hole, and the second electrode is inserted into and fixed to the second substrate hole.