According to an aspect of the invention, there is provided a semiconductor device including a plurality of memory cells, comprising a plurality of floating gate electrodes which are formed on a tunnel insulating film formed on a semiconductor substrate and have an upper portion which is narrower in a channel width direction than a lower portion, an interelectrode insulating film formed on the floating gate electrodes, and a control gate electrode which is formed on the interelectrode insulating film formed on the floating gate electrodes and partially buried between the floating gate electrodes opposing each other.