To provide lead frames for an optical coupling device, which can eliminate the occurrence of defective molding by preventing the occurrence of resin clogging on the air vent side while enhancing the working efficiency by preventing the occurrence of resin leakage at the time of transfer molding for eliminating the need for removing resin fins, and to provide a manufacturing method thereof.

The lead frames for the optical coupling device are configured so that a cradle 22a of one lead frame 21 having a greater width protrudes inward relative to a cradle 11a of the other lead frame 11. Fit portions 26, in which a tie bar 13 of the lead frame 11 is fitted, are provided in protrusions 29 of the cradle 22a; and a resin leakage blocking groove 40, which is linked to the fit portions 26 and open on the lead frame 11 side, is provided along the longitudinal direction of the cradle 22a.