An image display device that displays a thermal image that is captured by an infrared camera and indicates temperatures of a subject by color, the image display device comprising: a display unit configured to display the thermal image; a storage unit configured to store temperature-color conversion information representing a correspondence relation between temperatures of the subject and colors of a pixel; an operation unit configured to receive an operation of a user; and a control unit configured to, according to the operation of the user, generate the thermal image based on the temperature-color conversion information and cause the display unit to display the thermal image, wherein, the control unit is configured to, when a position on the thermal image is specified by the user, generate a temperature information image indicating, by a numerical value, a temperature of the position specified on the thermal image, and cause the display unit to display the temperature information image; characterized in that: the temperature information image indicates, by a numerical value, a temperature of each pixel contained in a predetermined area including the position specified on the thermal image; in the displayed temperature information image a temperature of a pixel corresponding to the position specified is displayed at a center of the temperature information image; and the control unit is configured to, when a position on the temperature information image is specified by the user, set a temperature range that has a predetermined temperature width and a center which is a temperature of a pixel corresponding to the position specified on the temperature information image, update the temperature-color conversion information based on the temperature range, regenerate the thermal image and the temperature information image based on the temperature-color conversion information updated, and cause the display unit to display the thermal image and the temperature information image which are regenerated. a display unit configured to display the thermal image; a storage unit configured to store temperature-color conversion information representing a correspondence relation between temperatures of the subject and colors of a pixel; an operation unit configured to receive an operation of a user; and a control unit configured to, according to the operation of the user, generate the thermal image based on the temperature-color conversion information and cause the display unit to display the thermal image, wherein, the control unit is configured to, when a position on the thermal image is specified by the user, generate a temperature information image indicating, by a numerical value, a temperature of the position specified on the thermal image, and cause the display unit to display the temperature information image; characterized in that: the temperature information image indicates, by a numerical value, a temperature of each pixel contained in a predetermined area including the position specified on the thermal image; in the displayed temperature information image a temperature of a pixel corresponding to the position specified is displayed at a center of the temperature information image; and the control unit is configured to, when a position on the temperature information image is specified by the user, set a temperature range that has a predetermined temperature width and a center which is a temperature of a pixel corresponding to the position specified on the temperature information image, update the temperature-color conversion information based on the temperature range, regenerate the thermal image and the temperature information image based on the temperature-color conversion information updated, and cause the display unit to display the thermal image and the temperature information image which are regenerated. the temperature information image indicates, by a numerical value, a temperature of each pixel contained in a predetermined area including the position specified on the thermal image; in the displayed temperature information image a temperature of a pixel corresponding to the position specified is displayed at a center of the temperature information image; and the control unit is configured to, when a position on the temperature information image is specified by the user, set a temperature range that has a predetermined temperature width and a center which is a temperature of a pixel corresponding to the position specified on the temperature information image, update the temperature-color conversion information based on the temperature range, regenerate the thermal image and the temperature information image based on the temperature-color conversion information updated, and cause the display unit to display the thermal image and the temperature information image which are regenerated.