On measuring the dielectric conatant of wood, we have pursued with the experimental method, edge cortection of the capacitance of wood between the parall capacitor, and attained the following approximate formula: (frequency is 1000 K. C.) εt=ε-pd/1+qd where: εt=corected dielectric constant, ε=apparent dielectric constant, d=thickness of dielectric snbstance, p, q=constants decided at the electrode.