Abstract: A semiconductor converter is provided with a cooling structure for cooling semiconductor units, resistors, and the like elements disposed in the housing of the semiconductor converter. A cooling air introduced into the housing through a cooling air intake port first cools the semiconductor units and the diverged cooling air flows after cooling the semiconductor units are converged at the location of a duct or passage formed between the semiconductor units and the resistors. The converged cooling air flow is directed towards the resistors to cool the same from the lower ones to the upper ones or vice versa in turn. An electric fan is installed in the air intake port or cooling air exhaust port for effectively circulate or flow the cooling air in the semiconductor converter.