To include two counter circuits that change impedances of two replica circuits, respectively, and an impedance adjustment control circuit that controls the counter circuits to update count values of the counter circuits. The impedance adjustment control circuit controls one of the counter circuits to finish updating the count value of the counter circuit in response to a change of the impedance of the corresponding replica circuit from a state of being lower than an impedance of an external resistor to a state of being higher than the impedance of the external resistor, and controls the other counter circuit to finish updating the count value of the other counter circuit in response to a change of the impedance of the other replica circuit from a state of being higher than the impedance of the former replica circuit to a state of being lower than the impedance of the former replica circuit. With this configuration, the adjust errors generated in the replica circuits are canceled.