A method for manufacturing an optical module 1 includes: a cladding 12 of one end of the optical fiber is exposed; an arrangement process of arranging the optical fiber 10 such that at least a leading end of a portion on which the cladding 12 is exposed is positioned in a box portion through a pipe portion 35 in which one end is connected to the box portion 31 configured to accommodate an optical element and which extends to an outside of the box portion 31; and a soldering process of soldering an inner wall of the pipe portion 35 and the optical fiber 10 by heating at least a part of a lower region BAR interposed between a heat dissipation portion and the pipe portion 35 in a state where a part of a wall of the box portion 31, in which the optical element is accommodated, is heat-dissipated.