According to an aspect of an embodiment, a memory controller for writing data into and reading data from a memory, comprises an error detector for detecting an error of data stored in the memory when reading the data, a time stamper for generating first time information indicative of the time when data is written into the memory, the first time information being written together with the data into an address location of the memory where the error has been detected, a timer for measuring a time period from the time indicated by the first time information until the time of subsequent occurrence of an error of data stored in said address location and a counter for counting a number of accesses to the address location over the time period.