A power conversion device includes a transformer circuit formed of a center-tapped isolation transformer, a rectifying circuit formed of a semiconductor switch element connected to the transformer circuit, a smoothing circuit formed of a capacitor connected to the rectifying circuit, a positive terminal and a negative terminal connected to a load, and a grounding surface to which the negative terminal is connected, wherein a current path along which only an AC current flows is shortened by a negative terminal of the isolation transformer and a negative terminal of the capacitor being connected before being connected to the grounding surface, or the negative terminal connected to the load and the negative terminal of the capacitor being connected before being connected to the grounding surface.