An optical disk device includes a read means which reads an image signal from an optical disk, and a conversion means which converts this image signal to one designated resolution. Furthermore, this optical disk device is connected to a display device which displays an image of this converted image signal. Moreover, this optical disk device includes an actuation means which receives input of one resolution among the first plurality of resolutions. And this optical disk device also includes a control means which acquires a second plurality of resolutions from the display device. And, when one resolution is inputted by the actuation means, this control means decides whether or not this input resolution is included in the second plurality of resolutions. Moreover, if it has been decided that the input resolution is included in the second plurality of resolutions, the control means designates that input resolution to the conversion means.