Improving agent for boiled fish-paste product, and boiled fish-paste product

The present invention improves tapioca starch to provide an excellent improving agent for a boiled fish-paste product, and also provides a boiled fish-paste product produced by adding the improving agent. Tapioca starch is acetylated with vinyl acetate to produce acetylated tapioca starch, which is oil-processed; the oil-processed acetylated tapioca starch is used as an improving agent for the boiled fish-paste product. Preferably, the oil-processed acetylated tapioca starch has an acetyl group content of 0.2 to 1 mass%, and, when a water suspension in which the concentration of the starch is 6 mass% in terms of dry matter is placed in a continuously heated state from 50 DEG C to 95 DEG C under stirring over 30 minutes and then held at 95 DEG C for another 30 minutes, the breakdown value found by subtracting the bottom viscosity after the suspension was held at 95 DEG C for 30 minutes from the peak viscosity of the starch suspension is 200 BU or less. Also, preferably, the degree of heated swelling is 20- to