In a method for manufacturing a module for a fiber optic link, a plate-shaped transparent circuit unit is molded in advance. The circuit module is transfer molded together with an optoelectronic element connected to leads. The circuit module is clamped between a pair of rod-shaped first dies which have a common central axis and one of which defines an optical path of the module, in such a manner that the optoelectronic element is located on a central axis of the circuit module. Under this condition, the circuit module is housed in a cavity defined by a pair of second dies. A light-shielding molding material is injected into the cavity for injection molding to mold a case. After the case is cured, the first and second dies are removed, and the hole of the case formed by one of the first die is closed with a cap to complete a receptacle.