To comprehensively utilize valuable components by softening cranial bones, and removing the source of nasty smell obstructing flavor, and excess oils and fats because although conventionally techniques for extracting the valuable components such as calcium, chondroitin sulfuric acid and collagen from fish scrap such as heads, tails and fins which cannot be used for a food in eel dish have been developed, the techniques are not the technique for comprehensively utilizing the components.

The delicious food having rich functions possessed by the eel is provided by the steps consisting of a step 1 for cleaning the fresh fish scrap of the eel and grilling the cleaned scrap, a step 2 for treating the grilled scrap at a high temperature of ≥100°C, a step 3 for removing the source of the nasty smell by a centrifugal separation, a step 4 for removing water therefrom, a step 5 for pulverizing the separated product, and a step 6 for powdering the pulverized product.