An optical module includes a housing, a printed circuit board, an optical assembly, an optical interface joined with the optical assembly, the printed circuit board, the optical assembly, and the optical interface being disposed in the housing, an adapter to be mated with an external optical connector and disposed on an end of the housing, and first and second connecting part disposed on the adapter and the housing, respectively. The adapter and the housing are secured together through the first and second connecting parts. The optical interface and the adapter are configured to correspond to each other.