Technique of improving a manufacturing yield of a semiconductor device including a non-volatile memory cell in a split-gate structure is provided. A select gate electrode of a CG shunt portion is formed so that a second height d2 from the main surface of the semiconductor substrate of the select gate electrode of the CG shunt portion positioned in the feeding region is lower than a first height d1 of the select gate electrode from the main surface of the semiconductor substrate in a memory cell forming region.