In the trap type memory chip the withstanding voltage is raised up, and then the electric current for reading out is increased. There are formed on the p-type semiconductor substrate 1 a first gate lamination structure which comprises a first insulating film 11 including a trap layer, and a first conductive body 9, and a second gate lamination structure which comprises a second insulating film 12 free of a trap layer and including an insulating film layer 13 doped with metal for controlling the work function at least on the upper layer, and a second conductive body 10. A source drain region 2 and a source drain region 3 are formed such that the first gate lamination structure and the second gate lamination structure are interleaved therebetween. The effective work function of the second gate lamination structure is higher than that of the first gate lamination structure.