Provided are: a semiconductor optical device having a reduced peeling rate of a wiring electrode section, while having a higher light extraction efficiency or light intake efficiency compared with conventional cases; and a method for manufacturing the semiconductor device. The present invention discloses a semiconductor optical device wherein: a wiring electrode section 120 is provided on the front surface of a semiconductor layer 110, said front surface being to be a light emitting surface or a light receiving surface; the line width W1 of the wiring electrode section 120 is 2-5 μm; the wiring electrode section 120 has a metal layer 121 on the semiconductor layer 110, and a conductive hard film 122 on the metal layer 121; and the conductive hard film 122 has a hardness that is higher than that of the metal layer 121.