A semiconductor laser device in a semiconductor-laser excited solid-state laser apparatus is provided with a plurality of semiconductor laser diodes connected in series to one another. Each of a plurality of bypass diodes is connected in parallel to each semiconductor laser diode or each group of at least two semiconductor laser diodes in the plurality of semiconductor laser diodes and has a higher rising voltage than a rising voltage of the parallel-connected semiconductor laser diodes. The polarity of one end of each of the semiconductors laser diode is the same as the polarity of that end of the associated bypass diode which is connected to the one end of that semiconductor laser diode and the polarity of the other end of the semiconductor laser diode is the same as the polarity of that end of the associated bypass diode which is connected to the other end of that semiconductor laser diode. This structure accomplish continuous light emission with a simple and compactable circuit structure even if one or more semiconductor laser diodes are disconnected, thereby making the semiconductor laser device highly reliable.