To provide a processing method not causing freshness deterioration of fish meat by degeneration change in quality and decomposition of internal organs in an acceptable processing range of food import examination requirements, readily identifying a nonpoisonous balloonfish simultaneously and improving freshness retention.

A head part of a balloonfish is cut off at a neck part from a body with leaving a skin at a body side, the skin at the body side left in cutting off the head part and a skin at a back side are simultaneously peeled to a position of a dorsal fin. In peeling the skins, internal organs separated from the body in a form of attached to the skin at the body side are removed. The skins peeled to the position of the dorsal fin are returned to the original positions and the balloonfish body is covered with the skins to restore the balloonfish to its original external form.