To realize a package capable of satisfying the positional accuracy required to maintain the positional relationship of a flexible light guide end and an optical element constant, a package including a supporting portion (10a) for supporting at least one end including an incident/exit port of a light signal in a light guide (4), an accommodating portion (10b) for accommodating an optical element (12) optically coupled with the light guide (4), and a lead frame (9) connected to the optical element (12) is manufactured by integral molding in the present invention. A die including a recess for forming the supporting portion (10a), a first projection (11b), which comes into contact with an optical element mounting surface (9a) of the lead frame (9) and forms the accommodating portion (10b), and a second projection (11c), which comes into contact with a back surface (9b) of the optical element mounting surface (9a) is used for the die.