PURPOSE: To provide a semiconductor memory circuit which can perform the optimum correction of errors by changing its correcting ability in accordance with each access speed.

CONSTITUTION: A semiconductor memory circuit contains an error detecting circuit 3 and an error correcting circuit 4 which are included in the same chip as a memory 2. Then the semiconductor memory circuit has at least one of following three functions. That is, a function (1) which corrects the errors by varying the error correcting ability of both circuits 3 and 4 when the errors are detected, a function (2) which does not correct the detected errors and outputs only the error detection flags, and a function (3) which outputs a waiting signal and keeps other processings waiting to correct the detected errors if the correction of errors are impossible due to an excessively high access speed.