To obtain a preventing agent for fish paste products from getting flaggy, capable of controlling conventional defective shapes of the products resulted from that the paste is so soft as to get flaggy in a molding process while maintaining a prescribed product quality without reducing a necessary water proportion in the paste, and to provide a method for producing the agent.

This is obtained by the following process; a hot water 1a at 60 to 100°C is mixed with an aqueous solution 2a of a powder material containing starch as the main component and the mixture is regulated so that the ratio for the powder material and water may be 1 vs. 3 to 20 pts.wt., subsequently the resultant hot aqueous solution with a reduced temperature caused by the mixing is reheated to 75 to 95°C under mixing, thus forming a pasty body.