A laser module, includes: an optical fiber; n laser diodes LDi (i=1, 2, . . . , n) arranged in an order corresponding to a descending order of optical path lengths LOi of optical paths respectively extending from the laser diodes LDi to the optical fiber; and n collimating lenses SLi respectively disposed in the optical paths to be distant from the respective laser diodes LDi and from the optical fiber. When a distance from each of the laser diodes LDi to a corresponding one of the collimating lenses SLi is defined as a collimation length LCi, at least one of a collimation length LC1 and a collimation length LCn differs from a certain distance SL that is set with respect to each of the collimating lenses SLi.