PURPOSE: To shorten the substituting time without increasing the area of a chip by selecting a preliminary signal line circuit corresponding to a signal input to a signal line circuit in activated by opening a circuit opening element by a selector.

CONSTITUTION: In order to replace bit lines BIT1,-BIT1 becoming improper with redundancy bit lines GIT1R,-BIT1R, a fuse FUSE is, for example, melted by a laser. Thus, a node 5 becomes 'H' by a transistor TP1, a node 6 becomes 'L', and the bit lines BIT1,-BIT1 are not permanently selected to be inactivated. Since the output of a gate NAND1 is 'L' and a transistor TP2 is turned ON, a node 12 is 'L' and a node 14 is 'H', thereby selecting redundancy bit lines BIT1R,-BIT1R. Thus, the increase in the area of a chip by a selector is suppressed, and the replacing time of the redundancy line can be shortened to reduce a chip cost.