A semiconductor integrated circuit device includes first and second nonvolatile semiconductor memories. The first memory has first and second select transistors and first memory cell transistors. The first memory cell transistor has a first floating gate on a first gate insulating film and a first control gate on a first inter-gate insulating film. The second memory has a third select transistor and a second memory cell transistor. The second memory cell transistor has a second floating gate on a second gate insulating film and a second control gate on a second inter-gate insulating film. The first and second gate insulating films have the same film thickness. The first and second floating gates have the same film thickness. The first and second inter-gate insulating films have the same film thickness. The first and second control gates have the same film thickness.