As Japanese population is aging, the importance of non-invasive and non-surgical periodontal treatment is increasing because elder people suffering from some systemic diseases and taking many medicines. The aim of periodontal treatment is to eliminate the biofilm in the periodontal pocket which is major etiologic factor of periodontal disease. A disadvantage of conventional non-surgical periodontal treatment using scaler is that accessibility of scaler to the bottom of pocket is not enough. Accessibility of the laser fiber is better than scaler, so the effect of biofilm removal is expected. However, as a point of consider, there is a problem of heat of generation. We discuss, here, the point of advantage of laser treatment rather than conventional methods and of a consideration for usage of laser.