To manufacture a woody cement board capable of preventing any warp or crack and excellent in dimensional stability.

The method of manufacturing a woody cement board comprises sequential mixing steps S1 to S4 of materials by using a Henschel mixer: step 1 wherein a mixture A is obtained by mixing a woody cement material of 100 pts.wt., a woody material of 5 to 30 pts.wt., an aggregate of 10 to 70 pts.wt., and a fiber of 0.5 to 10 pts.wt under condition of 0.04 to 0.09 kW/kg for a specified time; step 2 wherein a mixture B is obtained by adding a water of 15 to 60 pts.wt. while stirring the mixture A; step 3 wherein a mixture C is obtained by mixing the mixture B under condition of 0.20 to 0.35 kW/kg for a specified time; step 4 wherein a mixture D is obtained by mixing the mixture C under condition of 0.06 to 0.11 kW/kg for a specified time.