To enable reduction in size and cost of a pump device.

This pump device includes an electric motor 13 in a hollow shaped housing 11, a pressurized fluid generation mechanism 12 capable of generating negative pressure fluid by the electric motor 13, and a chamber 17 capable of accumulating pressure of the negative pressure fluid generated by the pressurized fluid generation mechanism 12. A body part of the electric motor 13 is disposed in the chamber 17.