According to the present invention, in the first place, in addition to gelatin, alginic acid or an alginate or a mannan is added thereto and mixed together with water to provide a starting material mixture. By the addition of these other substances to gelatin, the product obtained can be made similar in both mouth-feel and appearance to natural shark fins. As the alginate, sodium alginate is preferable. As the mannan, not only mannan in a narrow sense but also the mannan in a broad sense, including galactomannan, glucomannan and konjak-mannan, may be used.