In manufacturing a semiconductor memory by using conventional gain cells, it is difficult to integrate them similarly to 1T1C cells of a DRAM if mask alignment accuracy is considered. In order to achieve integration similarly to that of 1T1C cells by using gain cells, a memory cell block constituted as follows is used. A memory block (MCT) comprises a plurality of memory cells (MC0-MC3). Each memory cell includes a PMOS transistor (M0) for writing and an NMOS transistor (M1) for reading, and information is stored by holding electric charge in a storage node. The write transistors (M0) are arranged in parallel in a plurality of cells, each source-drain path is connected to a data line (DL). The read transistors (M1) are connected in series in a plurality of cells, and are connected to the data line (DL) via a block selection transistor (MB).