PURPOSE: To obtain a device, the quantity of reading signals thereof is much and an area of a dynamic memory cell thereof is not so much large, by a method wherein one of two MOSFETs forming the dynamic memory cell is made up by using a polycrystal semiconductor film.

CONSTITUTION: In an MOSFET1, a polycrystal Si film 11 formed on a P type Si substrate through a gate insulating film is used as a gate electrode, and an N+ type source 12 and a drain 13 are built up employing the polycrystal Si film 11 as a mask. An MOSFET2 with a source, a drain and a channel is made up on the extension of the polycrystal Si 11. A gate electrode of the MOSFET2 is formed by an N+ type layer 14 diffused and formed in the substrate, a bit line BL and a writing word line WLW are made up by the second layer polycrystal Si layer, and Al is evaporated through an insulating film and a bit line BL' and a reading word line WLR are built up.