To provide an optical module capable of preventing breakage of a lens and ensuring mounting accuracy of the lens when the lens is fixed to an inner hole of a housing, and having a lens fixing structure providing high workability.

A lens holder 3 has a lens holding part 3a for holding an optical lens 2, a press-fit part 3b to be press-fitted into an inner hole, and a connection part 3c for connecting the lens holding part 3a and the press-fit part 3b. The outer diameter of the lens holding part 3a is formed to be smaller than the inner diameter of the inner hole. A gap 4 is formed between the inner hole of a housing 1 and the lens holding part 3a. A groove is formed on the outer periphery of the connection part 3c. When the optical lens 2 is fixed to the lens holder 3, and the lens holder 3 is press-fitted into the inner hole of the housing 1 of a lens mounting unit 10, a stress generated at the time of the press-fitting does not directly act on the optical lens 2. This prevents the breakage of the optical lens.