A display device including a display unit having luminescence elements that individually become luminous depending on a current amount, the luminescence elements being arranged in a matrix pattern, the display device comprising: a luminescence amount regulator adapted to set a reference duty (DUTY) for regulating a luminescence amount per unit time for each of the luminescence elements according to picture information of an input picture signal; and an adjuster adapted to adjust, based on the reference duty (DUTY) provided by the luminescence amount regulator, an effective duty (DUTY') for regulating a luminous time for which the luminescence elements become luminous within a unit time, and to adjust a gain applied to the picture signal, so that a luminescence amount regulated with the effective duty (DUTY') and with the gain equals to the luminescence amount regulated with the reference duty (DUTY), and an average luminance calculator adapted to calculate an average luminance of the input picture signal for a predetermined period; wherein the luminescence amount regulator is adapted to set the reference duty depending upon the average luminance calculated by the average luminance calculator; characterized in that the adjuster includes a luminous time adjuster adapted to output, as the effective duty (DUTY'), a) the reference duty (DUTY) if the reference duty (DUTY) set by the luminescence amount regulator is within a predetermined range (L1-L2); or b) a predetermined lower or upper limit value if the reference duty set by the luminescence amount regulator is out of the predetermined range, and a gain adjuster adapted to adjust the gain of the picture signal, based on the reference duty (DUTY) set by the luminescence amount regulator and on the effective duty (DUTY') output from the luminous time adjuster, and further including: a primary gain adjuster adapted to multiply the input picture signal by the reference duty and a secondary gain adjuster adapted to divide the adjusted picture signal output from the primary gain adjuster by the effective duty output from the luminous time adjuster. a luminescence amount regulator adapted to set a reference duty (DUTY) for regulating a luminescence amount per unit time for each of the luminescence elements according to picture information of an input picture signal; and an adjuster adapted to adjust, based on the reference duty (DUTY) provided by the luminescence amount regulator, an effective duty (DUTY') for regulating a luminous time for which the luminescence elements become luminous within a unit time, and to adjust a gain applied to the picture signal, so that a luminescence amount regulated with the effective duty (DUTY') and with the gain equals to the luminescence amount regulated with the reference duty (DUTY), and an average luminance calculator adapted to calculate an average luminance of the input picture signal for a predetermined period; wherein the luminescence amount regulator is adapted to set the reference duty depending upon the average luminance calculated by the average luminance calculator; characterized in that the adjuster includes a luminous time adjuster adapted to output, as the effective duty (DUTY'), a) the reference duty (DUTY) if the reference duty (DUTY) set by the luminescence amount regulator is within a predetermined range (L1-L2); or b) a predetermined lower or upper limit value if the reference duty set by the luminescence amount regulator is out of the predetermined range, and a gain adjuster adapted to adjust the gain of the picture signal, based on the reference duty (DUTY) set by the luminescence amount regulator and on the effective duty (DUTY') output from the luminous time adjuster, and further including: a primary gain adjuster adapted to multiply the input picture signal by the reference duty and a secondary gain adjuster adapted to divide the adjusted picture signal output from the primary gain adjuster by the effective duty output from the luminous time adjuster. a luminous time adjuster adapted to output, as the effective duty (DUTY'), a) the reference duty (DUTY) if the reference duty (DUTY) set by the luminescence amount regulator is within a predetermined range (L1-L2); or b) a predetermined lower or upper limit value if the reference duty set by the luminescence amount regulator is out of the predetermined range, and a) the reference duty (DUTY) if the reference duty (DUTY) set by the luminescence amount regulator is within a predetermined range (L1-L2); or b) a predetermined lower or upper limit value if the reference duty set by the luminescence amount regulator is out of the predetermined range, and a gain adjuster adapted to adjust the gain of the picture signal, based on the reference duty (DUTY) set by the luminescence amount regulator and on the effective duty (DUTY') output from the luminous time adjuster, and further including: a primary gain adjuster adapted to multiply the input picture signal by the reference duty and a secondary gain adjuster adapted to divide the adjusted picture signal output from the primary gain adjuster by the effective duty output from the luminous time adjuster. a primary gain adjuster adapted to multiply the input picture signal by the reference duty and a secondary gain adjuster adapted to divide the adjusted picture signal output from the primary gain adjuster by the effective duty output from the luminous time adjuster.