To develop and provide: a rice flour making it possible to easily manufacture, at a bakery or at home, a highly expansible and finely textured 100% rice flour bread and a method for manufacturing a 100% rice flour bread using the rice flour. Provided are: a rice flour subjected to a preprocess in which rice flour, protease, and water are mixed to manufacture a rice flour dough and the rice flour dough is kept warm at 40°C to less than 60°C for 3-20 hours and a method for manufacturing a rice flour bread in which the rice flour is used.