We, in this article, propose an estimation method of the partially compression of the timber damaged by termite perpendicular to the grain. The estimation method was composed of the three parts, easy ways for judging existence or nonexistence of termite, detailed percussive analysis for quantitative estimating lack of the area by termite, and mechanical model for estimating partially compression of the termite timber perpendicular to the grain using lack of the area. The easy ways are conventional ways using observation, sounding of stroke and resisting presser of the screw driver, but originally proposed the concept of 500 effective lengths. Detailed percussive analysis was originally proposed frequency analysis of sound wave. The mechanical model was originally proposed.