To simplify the manufacturing step of the rising wall part of a storage node by forming a polysilicon film conductive, forming the storage node by the anisotropic etching of the polysilicon film and forming a capacitance insulating film and a cell plate.

An SiN film is formed by diffusing impurity ion into a polysilicon film and converting the polysilicon film conductive after forming the polysilicon film. The SiN film 7 as an insulating film is formed surrounding a gate electrode 4 and a word line 5 by the anisotropic etching of the SiN film. The spacing a between the gate electrode 4 and the word line 5 is provided and it is set to be smaller than the film thickness of a storage node. In the patterning of forming the storage node, the polysilicon film is left at the spacing a part and contacted to an N+ type source diffusion layer 8A. With this, the number of manufacturing steps of it is reduced and manufacturing process is simplified.