PURPOSE: To obtain paper having excellent paper strength, yield of fillers and evenness, by gelatinizing starch particles with mechanical means such as impact, adding the gelatinized starch particles to pulp slurry and making to paper.

CONSTITUTION: Starch particles (preferably raw starch particles or chemically modified starch particles chemically modified OH groups in the starch particles) are treated so that at least a part of the starch particles is gelatinized by a mechanical means having several actions such as impact, flat crush, friction and shearing, preferably in a mixing state with pigment. Resultant gelatinized starch particles are added to a pulp slurry and made to afford the aimed paper.