Abstract: An image signal processing device has an LSI including a ROM access control circuit for holding data for controlling an operation of a video signal processing unit, and a flush ROM that is disposed outside the LSI, holds control data to be transmitted to the ROM access control circuit, and allows data read to be controlled by the ROM access control circuit. The data transferred between the flush ROM and the ROM access control circuit has data that must be updated every field and data that does not need to be updated every field. The data is transferred in a vertical blanking time period of the video output data. This configuration allows certain transfer of required data using the vertical blanking time period.