An equalizer control device includes a first circuit configured to, upon receipt of a data signal that has been equalized by a continuous time linear equalizer (CTLE) circuit, output a first signal related to a first number of times a waveform of the data signal crosses a threshold value or differential signals of the data signal cross each other. A second circuit is configured to count the first number during a particular time period based on the output first signal, and select one of equalization parameters to be set to the CTLE circuit based on the counted first number.