A printing apparatus measures a temperature of an electrothermal transducer by a corresponding temperature detection element, detects, based on the measured temperature, a peak voltage which indicates a point of change, from a state where ink is discharged normally from a printhead to a state where the ink is not discharged from the printhead, and compares the peak voltage with a threshold value. The measurement, detection, and comparison are repeated until the peal voltage becomes equal to or more than the threshold value. Energy supplied to the electrothermal transducer at a time in which the peak voltage is determined to be equal to or more than the threshold is determined to be minimum discharge energy.