A motor-driven compressor includes a compression unit, an electric motor, a drive circuit, a first housing, a second housing, and a soundproofing material. The second housing covers at least part of an outer surface of the first housing. The soundproofing material is arranged between the outer surface of the first housing and an area that includes an inner surface and a wall surface of the second housing. The soundproofing material has sound insulating properties. The soundproofing material includes a sound absorbing layer and a sound insulating layer. A first region and a second region are formed between the outer surface of the first housing and the area that includes the inner surface and the wall surface of the second housing. An air layer is formed in the second region.