A semiconductor device includes an address conversion circuit which generates the second address for storing an error detecting code in a memory based on the first address for storing data; a write circuit which writes data at the first address and writes an error detecting code at the second address; and a read circuit which reads data from the first address, reads the error detecting code from the second address, and detects an error based on the data and the error detecting code. The address conversion circuit generates an address as the second address by modifying the value of at least one bit of the first address so as to offset the storing position of the error detecting code to the storing position of the data, and by inverting the value of or permutating the order of the prescribed number of bits among the other bits.