In a semiconductor apparatus, a plurality of light-triggered type semiconductor devices, each having a groove for burying of an optical fiber for supplying an optical gate signal to a housing of the light-triggered type semiconductor device, are connected in series. Device cooling heat sinks, each having a flow path for circulating a coolant medium and a coolant inlet and a coolant outlet communicating with the flow path, are disposed on both sides of the housing of each light-triggered type semiconductor device. The light-triggered type semiconductor devices and the device cooling heat sinks are coupled into a single structure. An optical fiber insertion groove, which corresponds in position to the groove of the housing, is provided on a side surface of the device cooling heat sink, which contacts a groove (4)-side surface of the housing of the light-triggered type semiconductor device.