A cooling structure of a semiconductor device includes an output electrode, a semiconductor element and a semiconductor element disposed to face each other with the output electrode interposed therebetween, a radiator disposed for the semiconductor element on a side opposite to the output electrode, and a radiator disposed for the semiconductor element on the side opposite to the output electrode. The output electrode includes an element mounting portion and a heat transport portion. The element mounting portion is electrically connected to the semiconductor element and the semiconductor element, and is formed of a conductive material. The heat transport portion is disposed to extend from the element mounting portion toward the radiator and the radiator. With this structure, a cooling structure of a semiconductor device with which excellent cooling efficiency is realized can be provided.