A lead frame or semiconductor device and a method of manufacturing the same in which where the unit lead frame of each semiconductor device after dicing was located in a lead frame before dicing can be known without an additional manufacturing step. The lead frame includes a plurality of unit lead frames each having a die pad, suspension leads coupled to the die pad, and leads formed around the die pad. An identification mark including at least one of a penetrating groove, recess, and convex is formed in at least one of the die pad, suspension leads, and leads. The identification mark of a first unit lead frame and the identification mark of a second unit lead frame are different from each other at least either in location in the unit lead frame or in shape.