PURPOSE: To enhance the relief efficiency of a dynamic RAM having a redundant word line and a redundant bit line and to enhance the product yield by disposing a redundant element on the part having relatively large process margin of the surface of a semiconductor substrate.

CONSTITUTION: The semiconductor device comprises a redundant element disposed on the part having relatively large process margin of the surface of a semiconductor substrate. For example, the element has a redundant word line in which the drive route between its X-address decoder is selectively disconnected when it is not used and a redundant bit line in which the drive route of a corresponding unit amplifier is selectively disconnected when it is not used. Such redundant word line WR00 to WR03, WR10 to WR13 as well as the redundant bit lines BR0* to BR7* are disposed together at the central part having relatively large process merging of memory arrays ARY0 and RY2 including corresponding redundant memory cells.