A switch board of a board unit includes a switch board including an exposed portion exposed to an outside, a non-exposed portion not exposed to the outside, and a switch provided in the non-exposed portion. The non-exposed portion of the switch board is covered with the cover portion. The cover portion is formed as one piece with the switch board in the state in which liquid-tightness is kept between the cover portion and the non-exposed portion, and liquid is prevented from flowing from the outside of the board unit into the non-exposed portion.
