An optical communication module includes an optical package including at least one semiconductor optical device, an optical filter for reflecting light of a specific wavelength and transmitting light of an other wavelength, an optical block including a transparent material and the optical filter, a housing that houses the optical package and the optical block, an in-housing circuit board housed in the housing and mounting a peripheral electrical circuit for the optical package thereon, and an electrical connector electrically connected to the in-housing circuit board and exposed at a bottom surface of the housing. The optical block further includes a front lens portion at a front side face of the housing, a rear lens portion at a rear side face of the housing, a light inputting port, and a light outputting port. The optical filter is arranged to obliquely intersect with an optical axis passing through the front lens portion and the rear lens portion at a predetermined angle. The optical package is arranged such that an optical axis between the optical filter and the optical package is substantially orthogonal to an optical axis between the front lens portion and the optical filter.