An improved SRAM is disclosed including a plurality of memory blocks each having a redundancy memory cell to be shared. In redundancy row decoders 50a, 50b, 50c provided in each memory block, a memory block to be remedied is programmed. Accordingly, a redundancy memory cell row corresponding to each redundancy row decoder can be used for remedy of a defect memory cell in another memory block. Since a defect memory cell may be remedied flexibly, the yield rate in production of semiconductor memories is improved.