A display device configured to display an image indicated by an HDR signal and an image indicated by an SDR signal, the display device comprising: a display panel ; a panel control unit configured to control the display panel; and a first image processing unit , wherein the first image processing unit is configured to perform gradation performance conversion of converting, in accordance with a maximum luminance level indicated by the HDR signal input to the first image processing unit, a gradation performance which is a gradation value or luminance information indicated by the HDR signal, with reference to a tone map indicating a relationship between luminance information before the conversion and luminance information after the conversion into a prescribed gradation performance according to the display panel, and the panel control unit is configured to perform gradation value conversion of converting, in accordance with the maximum luminance level indicated by the HDR signal and a maximum luminance displayable by the display panel, a gradation value indicated by an HDR signal after the gradation performance conversion into a gradation value displayable by the display panel, the display device further comprises a superimposed image generation unit including a gain adjustment unit configured to change a gradation level of a superimposition target image depending on whether an input signal is the HDR signal or an SDR signal, and the superimposed image generation unit is configured to superimpose the superimposition target image on an image indicated by the HDR signal after the gradation performance conversion by the first image processing unit. a display panel ; a panel control unit configured to control the display panel; and a first image processing unit , wherein the first image processing unit is configured to perform gradation performance conversion of converting, in accordance with a maximum luminance level indicated by the HDR signal input to the first image processing unit, a gradation performance which is a gradation value or luminance information indicated by the HDR signal, with reference to a tone map indicating a relationship between luminance information before the conversion and luminance information after the conversion into a prescribed gradation performance according to the display panel, and the panel control unit is configured to perform gradation value conversion of converting, in accordance with the maximum luminance level indicated by the HDR signal and a maximum luminance displayable by the display panel, a gradation value indicated by an HDR signal after the gradation performance conversion into a gradation value displayable by the display panel, the display device further comprises a superimposed image generation unit including a gain adjustment unit configured to change a gradation level of a superimposition target image depending on whether an input signal is the HDR signal or an SDR signal, and the superimposed image generation unit is configured to superimpose the superimposition target image on an image indicated by the HDR signal after the gradation performance conversion by the first image processing unit. <EOS>