A lead frame for mounting LED elements includes a frame body region and a large number of package regions arranged in multiple rows and columns in the frame body region. The package regions each include a die pad on which an LED element is to be mounted and a lead section adjacent to the die pad, the package regions being further constructed to be interconnected via a dicing region. The die pad in one package region and the lead section in another package region upward or downward adjacent to the package region of interest are connected to each other by an inclined reinforcement piece positioned in the dicing region.