An information processing device includes: a receiver that compares a serial input signal to a threshold value and outputs reception data; an extraction circuit that extracts a clock superimposed on the reception data from the reception data; a measurement circuit that measures a pulse width of the reception data based on the clock; a counter that measures an elongation and a shortening of the pulse width; and an adjustment circuit that increases the threshold value when the elongation of the pulse width is larger than a reference value, and reduces the threshold value when the shortening of the pulse width is larger than the reference value.