To provide a manufacturing method for a differential phase modulated light receiving module can reduce a cost and can make a size compact, while keeping the consistency of delay of a differential signal flowing between a delay interferometer and a balanced receiver in an inside of the balanced receiver, and the differential phase modulated light receiving module.

This light receiving module 10 is provided with the delay interferometer 12, the balanced receiver 14, and a pair of optical fibers 20 for guiding a light emitted from the delay interferometer 12 to the balanced receiver 14. Each of the paired optical fibers 20 is formed by fusion-connecting a plurality of fellow optical fiber members. An optical path length difference is provided between the paired optical fibers 20, to absorb a difference between an optical path length difference n an inside of the delay interferometer 12 and/or an optical path length difference in an inside of the balanced receiver 14, and a prescribed optical path length difference.