A data buffer section stores input words, and outputs them to a first signal line group in order. An error checking and correcting code is generated that has the same number of bits as the words. Some bits are not to be output at the same time within the range of the first and second signal line groups or within the range of a partial signal line group included in the first and second signal line groups. A code transmission section outputs the error checking and correcting code to different signal lines of the second signal line group respectively, such that a plurality of bits in a code word are not output at the same time within the range of the first and second signal line groups or within the range of a partial signal line group included in the first and second signal line groups.