To obtain a pregelatinized starch having excellent dispersibility, readily providing a uniform paste solution free from undissolved lump of flour and lump, useful as a thickening agent, an adhesive an oil absorbing agent, etc., by mixing a starch slurry with a specific amount based on a starch of an emulsifying agent and subjecting the mixture to drum drying.

A starch slurry (e.g. a starch slurry having 30-50% concentration useful in the general production of pregelatinized starch) is mixed with 0.1-10% based on a starch of an emulsifying agent, dried and pregelatinized by a routine procedure by a drum dryer. Natural starches such as potato starch, maize starch, tapioca starch, sweet potato starch, wheat starch, sago starch, rice starch, etc., starch derivatives obtained by treating them with an acid, oxidizing them or treating with an enzyme, etherifying, esterifying or cross-linking them may be cited as the starch. Calcium stearoyllactate, a propylene glycol fatty acid ester, a sorbitan fatty acid ester, etc., may be cited as the emulsifying agent.