A display device comprises a nonvolatile memory for storing an amount of adjustment obtained in a blanking adjustment most recently performed for a particular video signal, means for judging whether or not the particular video signal is inputted, means for masking a region defined by the amount of adjustment, obtained in the blanking adjustment, stored in the nonvolatile memory at a black level when the particular video signal is inputted, means for allowing the blanking adjustment based on a user operation only when the particular video signal is inputted, and means for updating the amount of adjustment, obtained in the blanking adjustment, stored in the nonvolatile memory, when it is changed by the user operation, to the changed amount of blanking adjustment.