A plaster board including a plaster core having a front surface, a back surface, two opposite side surfaces and two opposite end surfaces and a covering base paper covering the front surface, back surface, and two opposite side surfaces, which core includes high-density hard edge parts including the two opposite side surfaces, at least one high-density part including the front or back surface, and having a density substantially equal to densities of the high-density hard edge parts, and a central low-density part having a density less than the densities of the high-density hard edge parts and the high-density part and being inscribed in the high-density hard edge parts and the high-density part, wherein each of the high-density hard edge parts is formed so as not to be present in the nailing area along longitudinal directions of the board in which a nail for fixing the board is driven.