The object is to enable the user to selectively set the notification of a gamut error and notification deactivation condition. For this, a detection unit 3 detecting a gamut error of an input image signal, and a plurality of notifying units 5, 8 and 6, 9 and 11 notifying that a gamut error has occurred in different methods from each other are provided. And, a setting unit 15 carrying out the operation of setting which of these notifying units is to be caused to carry out notification and the operation of setting the condition for deactivating notification of a gamut error is provided. The information indicating the setting result by the setting unit 15 is stored in a storage unit 14. Further, under control of a control unit 13, based on that a gamut error has been detected by the detection unit 3, the notifying units indicated by the information acquired from the storage unit 14 is caused to carry out notification of a gamut error and deactivation of notification of a gamut error under the condition indicated by the information.