PURPOSE: To inspect an address decoder in real time and improve the reliability of a semiconductor storage circuit by comparing address information passed through a decoder and an address information storage part with address information generated by an address information generation part.

CONSTITUTION: The address information from an input terminal 10 is decoded by an address decoder 11 to read the address information for access to a data storage part 30 out of the address information part 31. This address information is compared with the address information that the address information generation part 40 such as a through circuit generates by a comparator 41 composed of an exclusive OR circuit, and if even one bit is found dissident, the state defect signal of the decoder 11 is generated at a comparison result output terminal 42. Thus, the address decoder is checked in real time and the reliability of the semiconductor storage circuit is improved.