A high voltage unit installed in a vehicle includes a high voltage component and a casing that accommodates the high voltage component. The casing includes a side wall provided with a pressure receiving portion that receives impact in a horizontal direction and a planer portion on which the high voltage component is arranged, the planer portion being adjacent to an inner side of the side wall. The high voltage component is arranged on the planer portion with a gap from the side wall provided with the pressure receiving portion. An area corresponding to the gap of the planer portion includes a portion, between the pressure receiving portion and the high voltage component, provided with a brittle portion, and includes a portion, other than the brittle portion, provided with a high strength portion having higher strength than the brittle portion.