An image signal generation portion 11 generates an image signal of a variable frame-rate picked-up image. A signal generation control portion 24 drives the image signal generation portion 11 and generates image pick-up setting information IF to generate an image signal that is frame-synchronized with a generated image signal DVd. The generated image signal DVd is output in condition where the image pick-up setting information IF is inserted in it. When supplied with image pick-up setting information IFex, the signal generation control portion 24 controls the driving operations of the image signal generation portion 11 based on the image pick-up setting information IFex, to frame-synchronize the generated image signal with an image signal of a reference variable frame-rate picked-up image of a source that has supplied the image pick-up setting information IFex. If a plurality of image pick-up devices capable of varying a frame rate is used, the image signals can be frame-synchronized with each other.