A urea concentration identification device and a urea concentration identification method are provided. By providing an identical sine-wave AC signal to each of the urea concentration identification devices placed in urea solutions of different concentrations, different impedance values are output by the urea concentration identification devices since the urea solutions of different concentrations have different electrical interactions with the electrodes of the urea concentration identification device. Differences of the impedance output by the urea concentration identification device function as a data set for determining the concentration of the urea solution to be determined.