To provide base paper which is not buckled and deformed, prevents buckling on the way of transportation, can prevent the falling and the like of a sheet, and is used for paper boxes for laminated sheets, to provide a paper box used for laminated sheets and using the base paper, and to provide a paper box used for laminated sheets and having excellent moisture-absorbing or releasing aptitude.

This paper box for laminated sheets comprising paperboard having a structure of three or more layers comprising a middle layer and outer layers disposed on both the sides of the middle layer is characterized in that the total density of the paperboard is 0.65 to 0.85 g/cm3; the density of at least one of the outermost layers is 0.75 to 0.90 g/cm3; the middle layer consists mainly of one or more kinds of pulp selected from the group consisting of mechanical pulp, curled fibers and mercerized pulp; the density of the middle layer is 0.40 to 0.75 g/cm3; a basis weight is 250 to 480 g/m2 ; and a specific stiffness value (value obtained by dividing the geometrical mean value of longitudinal and latitudinal taper stiffness values by the basis weight) is ≥0.050 mN×m3/g. The paper box for laminated sheets is produced from the raw paper for paper boxes.