A semiconductor memory including a plurality of cell units arranged in a row direction, each of the cell units includes: a semiconductor region; a first buried insulating film provided on the semiconductor region; a second buried insulating film provided on the first buried insulating film, which has higher dielectric constant than the first buried insulating film; a semiconductor layer provided on the second buried insulating film; and a plurality of memory cell transistors arranged in a column direction, each of the memory cell transistors having a source region, a drain region and a channel region defined in the semiconductor layer.