A semiconductor laser assembly includes a substrate 10 having a first mount surface 10a and a second mount surface 10b, and a submount 3 which is mounted on the first mount surface 10a and which is separate from a monitoring photodiode 4. A laser diode 1 is mounted on the submount 3. The monitoring photodiode 4 is mounted on the second mount surface 10b, and an electrode 4a formed on the monitoring photodiode 4 is used as a relay electrode for a metal wire 5a connected to an upper-surface electrode of the laser diode 1.