To manufacture wood products hardly gathering mold, at a relatively low cost without sacrificing water absorption capability and moisture release capability of the wood products.

In manufacturing wood products, they are immersed in a solution containing 0.05 wt.% to 1.00 wt.% of soap for a prescribed time period, and then the immersion is further continued under a reduced pressure within the range from -20 Kpa(G) to -100 Kpa(G).