A process of producing whole wheat flour including the steps of (1) coarsely grinding wheat kernels, (2) separating the resulting ground product into a fine fraction with an average particle size less than a size ranging from 150 to 200 .mu.m and a coarse fraction with an average particle size more than that of the fine fraction and at or above a size ranging from 150 to 200 .mu.m, (3) pulverizing the coarse fraction by impact grinding, (4) fractionating the resulting ground product obtained in step (3) to collect a fine fraction with an average particle size less than a size ranging from 150 to 200 .mu.m, and (5) combining the fine fraction from step (2) and the fine fraction obtained in step (4). Preferably, the coarse fraction obtained in step (2) is subjected to a heat-moisture treatment, and the heat-moisturized fraction is pulverized by impact grinding in step (3).