To provide the manufacturing method of a lead frame which produces no irregularities in the tip of an inner lead, when manufacturing lead frames processed by display treatment in the inner lead and an island part, and also the lead frames having different depths when viewed from side surface.

This manufacturing method of a lead frame is provided at least with a step for forming an island part 2, an inner lead 3 and an outer lead the island part 2 which is depressed deeper than the depressed inner lead 3, contains at least a process wherein a tabular lead frame, where the island part 2 and the inner lead 3 are connected, is manufactured, a process where the desired display treatment is performed at least on the inner lead 3, a process where the island part 2 and the inner lead 3 are cut, and a process where display treatment is performed on the island part 2, as necessary.