A method for producing rice flour, comprising the steps of: soaking of material rice and obtaining a soaked material rice, adjusting moisture content of the soaked material rice to obtain a soaked and moisture-adjusted material rice, primary crushing of the soaked and moisture-adjusted material rice using a disintegrating and sizing device and obtaining a primary crushed rice having a smaller size than the soaked and moisture-adjusted material rice, the primary crushing step including: feeding the soaked and moisture-adjusted material rice into a particle size adjustment region of the disintegrating and sizing device, the particle size adjustment region including a gap region terminating in a gap of a predetermined size provided between a rotating surface of a rotating body and an opposite surface, the opposite surface being a surface selected from surfaces of an inlet section that extends from a casing of the disintegrating and sizing device into the gap region, allowing passage of finely ground rice particles matching the predetermined gap size through the particle size adjustment region and discharging the particles matching the predetermined gap size through a discharge port, retaining finely ground rice particles not matching the predetermined gap size within the particle size adjustment region, disintegrating retained particles not matching the predetermined gap size into the particles matching the predetermined gap size by contacting the retained particles between the rotating surface and the opposite surface while rotating the rotating body, and discharging the disintegrated particles matching the predetermined gap through the discharge port; fine grinding of the primary crushed rice using an air mill and obtaining a finely ground rice having a smaller size than the primary crushed rice, and drying the fine ground rice with an air flow dryer. soaking of material rice and obtaining a soaked material rice, adjusting moisture content of the soaked material rice to obtain a soaked and moisture-adjusted material rice, primary crushing of the soaked and moisture-adjusted material rice using a disintegrating and sizing device and obtaining a primary crushed rice having a smaller size than the soaked and moisture-adjusted material rice, the primary crushing step including: feeding the soaked and moisture-adjusted material rice into a particle size adjustment region of the disintegrating and sizing device, the particle size adjustment region including a gap region terminating in a gap of a predetermined size provided between a rotating surface of a rotating body and an opposite surface, the opposite surface being a surface selected from surfaces of an inlet section that extends from a casing of the disintegrating and sizing device into the gap region, allowing passage of finely ground rice particles matching the predetermined gap size through the particle size adjustment region and discharging the particles matching the predetermined gap size through a discharge port, retaining finely ground rice particles not matching the predetermined gap size within the particle size adjustment region, disintegrating retained particles not matching the predetermined gap size into the particles matching the predetermined gap size by contacting the retained particles between the rotating surface and the opposite surface while rotating the rotating body, and discharging the disintegrated particles matching the predetermined gap through the discharge port; fine grinding of the primary crushed rice using an air mill and obtaining a finely ground rice having a smaller size than the primary crushed rice, and drying the fine ground rice with an air flow dryer. feeding the soaked and moisture-adjusted material rice into a particle size adjustment region of the disintegrating and sizing device, the particle size adjustment region including a gap region terminating in a gap of a predetermined size provided between a rotating surface of a rotating body and an opposite surface, the opposite surface being a surface selected from surfaces of an inlet section that extends from a casing of the disintegrating and sizing device into the gap region, allowing passage of finely ground rice particles matching the predetermined gap size through the particle size adjustment region and discharging the particles matching the predetermined gap size through a discharge port, retaining finely ground rice particles not matching the predetermined gap size within the particle size adjustment region, disintegrating retained particles not matching the predetermined gap size into the particles matching the predetermined gap size by contacting the retained particles between the rotating surface and the opposite surface while rotating the rotating body, and discharging the disintegrated particles matching the predetermined gap through the discharge port; fine grinding of the primary crushed rice using an air mill and obtaining a finely ground rice having a smaller size than the primary crushed rice, and drying the fine ground rice with an air flow dryer.