In a phase adjustment device according to the present invention, a first luminance level detector detects a luminance level of a digital imaging signal in a first pixel region, a second luminance level detector detects a luminance level of the digital imaging signal in a second pixel region, a data comparator compares detection results by the first and second luminance level detectors, an adjustment judger judges if it is necessary to adjust a phase of a pulse based on a result of the comparison by the data comparator, a timing adjuster shifts the phase of the pulse in the second pixel region when the luminance levels are detected, and further, the timing adjuster adjusts the phase of the pulse when the judgment by the adjustment judger indicates that the phase adjustment is necessary.