A first oxide film (102) and a first nitride film (103) are formed over a semiconductor substrate (101) so as to be stacked in this order. A plurality of first gate electrodes (104) are arranged on the first nitride film (103) so as to be spaced apart from one another with a predetermined distance therebetween. Upper part and side walls of each of the first gate electrode (104) is covered by a second oxide film (105). The second oxide film (105) and part of the first nitride film (103) located between the first gate electrodes (104) are covered by the second nitride film (106). A plurality of second gate electrodes (107) are formed on at least part of the second nitride film (106) located between adjacent two of the first gate electrodes (104). Each of the second gate electrodes (107) is separated from the first gate electrode (104) by the second oxide film (105) and the second nitride film (106) and separated from the semiconductor substrate (101) by the first oxide film (102), the first nitride film (103) and the second nitride film (106).