Data of 2-bits prefetched from a memory array and transmitted to an amplifying circuit via a data bus is ordered in accordance with the least significant bit of a column address which is a start address supplied from the outside. The first data is output to read data buses and is directly transmitted to an output data latch. The second data is held once by a second data latch and, after that, transmitted to the output data latch. Since the first data is transmitted from the amplifying circuit directly to the output data latch, the time from a read command is received until data is started to be output can be shortened.