An inverter apparatus includes a liquid path in which cooling water flows, and in which the cooling water performs cooling at a cooling part located directly underneath the power circuit part of the inverter apparatus. The liquid path includes a first partial structure part formed between a feed pipe and the cooling part, and having a liquid path cross-sectional profile that is gradually reduced in the short-side direction of the cooling part and that is gradually enlarged in the long-side direction thereof; and a second partial structure part formed between the cooling part and a drain pipe, and having a liquid path cross-sectional profile that is gradually enlarged from the short-side of the cooling part and that is gradually reduced from the long-side thereof.