An AV amplifier detects combinations of resolutions and vertical frequencies of input video data, and reads information about combinations of resolutions and vertical frequencies stored in a display device in advance. The AV amplifier sets values, that are a combination of an output resolution and an output vertical frequency in which a value obtained by dividing a vertical frequency of the video data detected by a video detecting section by the output vertical frequency is an integer number and are present in the combinations of the resolutions and the vertical frequencies read by the reading section, as the combination of the output resolution and the output vertical frequency.