Chemical investigation of milk which had been consumed in Okayama prefacture from Agust in 1956 to June 1957 has been done. About 170 samples were collected at 10 regions (A-J in Fig. 1), and pH, titratable acidity, fat content by Gerber method, protein content by Kjedahl method, lactose content by Lane-Eynone method and milk solid of them were determined. Results obtained are summarised as follows; 1) The great part of samples were within the range of 3.20～3.70% of fat, 2.60～3.30% of protein, 4.10～4.40% of lactose, and 0.13～0.16% of acidity, respectively. On the average of them, the fat content was higher than that of whole land and the lactose content was slightly lower. 2) In summer, the decrease of protein content was remarkedly but the fat content was even in all seasons.