Raw wheat grains are polished after being subjected to a first water addition and being tempered, and the polished wheat grains are ground after being subjected to a second water addition and being tempered. The first water addition is to cause the raw wheat grains to have a water content of 12-14%. The tempering of the raw wheat grains is performed for 16-36 hours so that the water sufficiently penetrate into the inside of the raw wheat grains. The method of flouring includes the steps of measuring a water content of the flour obtained by the grinding of the grains, comparing the amount of the measured water content with a predetermined target water content of the flour, and adjusting the amount of water to be added during the second water addition if there is a difference between the measured water content and the predetermined target water content. Thus, it is possible to reduce the time required for the tempering of the polished wheat grains and to adjust the second water addition based on the water content in the flour.