A variable delay circuit provides an adjustable delay to a strobe signal. An input latch circuit latches each bit data included in internal serial data by a strobe signal delayed by the variable delay circuit. A delay set unit adjusts a delay amount provided to the strobe signal by the variable delay circuit. While a calibration operation is being executed in which a known calibration pattern is inputted as serial data, the delay set unit statistically acquires output latch data of the input latch circuit, and adjusts the delay amount such that probabilities of occurrence of 1 and 0 becomes a predetermined ratio.