A light source device and an exposure device are disclosed. A light source device includes: a semiconductor laser; a coupling lens; a holder; a sheet-metal member and a photopolymerizable resin. The coupling lens converts laser light from the semiconductor laser to a light flux. The coupling lens has an optical axis. The sheet-metal member holds the semiconductor laser and the coupling lens. The photopolymerizable rein is cured to fix the coupling lens on the sheet-metal member.An exposure device for forming an electrostatic latent image by scanning light on a photosensitive body includes: a light source device having a semiconductor laser; a coupling lens, a sheet-metal member and a photopolymerizable resin, a deflector and a scanning lens.