Semiconductor laser device and wire bonding method capable of easily performing reliable wire bonding

There is provided is a semiconductor laser device capable of simplifying fabricating processes with a simple construction and easily mounting two semiconductor laser elements and a monitoring PD on a compact package and a wire bonding method for the semiconductor laser device. There are provided a stem 100 provided with a plurality of lead pins 121 through 124, a sub-mount 160 that is die-bonded onto the stem 100 and has its surface formed integrally with a monitoring PD 140 and two semiconductor laser elements 131 and 132 that are die-bonded onto the sub-mount 160 and have emission light monitored by the monitoring PD 140. A first bonding surface i.e. anode electrode 183 of the monitoring PD 140 and a second bonding surface i.e. end surface 123a of a lead pin 123 that is approximately perpendicular to the first bonding surface are wire-bonded to each other.