A semiconductor device of the present invention includes: an element isolation part which is disposed between fins and whose height is lower than the height of each fin; a memory gate electrode placed over the fins and the element isolation part with a memory gate insulating film having a charge storage part in between; and a control gate electrode disposed in line with the memory gate electrode. The height of the element isolation part below the memory gate electrode is higher than the height of the element isolation part below the control gate electrode. A mismatch between electron injection and hole injection is improved, rewriting operation speed is accelerated, and reliability is enhanced by making the height of the element isolation part below the memory gate electrode higher than the height of the element isolation part below the control gate electrode as mentioned above.