A device for rolling a metal sheet material, comprising: a top work roll and a bottom work roll that roll a metal sheet material; a top back up roll and a bottom back up roll that support the top work roll and the bottom work roll, respectively; a top work roll chock and a bottom work roll chock that support the top work roll and the bottom work roll, respectively; a top back up roll chock and a bottom back up roll chock that support the top back up roll and the bottom back up roll, respectively; a housing that accommodates the top work roll chock, the bottom work roll chock, the top back up roll chock, and the bottom back up roll chock, the housing including a pair of first project blocks (5-1, 5-2) protruding inwardly that bears a force in a rolling direction acting on the bottom work roll, first hydraulic cylinders (6-1, 6-2) provided to the pair of first project blocks (5-1, 5-2) and each including a first piston rod that applies an increase-bending force by way of the top work roll chock to the top work roll; and second hydraulic cylinders (6-3, 6-4) provided to the pair of first project blocks (5-1, 5-2) and each including a second piston rod that applies an increase-bending force by way of the bottom work roll chock to the bottom work roll; characterized in that the housing further includes a housing window that bears a force in the rolling direction acting on the top work roll, and the device further comprises third hydraulic cylinders (7-1, 7-2) provided to the top back up roll chock and each including a third piston rod that applies a decrease-bending force to the top work roll or that brings the top work roll into contact with the top back up roll to generate a roll balance force; and fourth hydraulic cylinders (7-3, 7-4) each including a fourth piston rod that applies a decrease-bending force to the bottom work roll. a top work roll and a bottom work roll that roll a metal sheet material; a top back up roll and a bottom back up roll that support the top work roll and the bottom work roll, respectively; a top work roll chock and a bottom work roll chock that support the top work roll and the bottom work roll, respectively; a top back up roll chock and a bottom back up roll chock that support the top back up roll and the bottom back up roll, respectively; a housing that accommodates the top work roll chock, the bottom work roll chock, the top back up roll chock, and the bottom back up roll chock, the housing including a pair of first project blocks (5-1, 5-2) protruding inwardly that bears a force in a rolling direction acting on the bottom work roll, first hydraulic cylinders (6-1, 6-2) provided to the pair of first project blocks (5-1, 5-2) and each including a first piston rod that applies an increase-bending force by way of the top work roll chock to the top work roll; and second hydraulic cylinders (6-3, 6-4) provided to the pair of first project blocks (5-1, 5-2) and each including a second piston rod that applies an increase-bending force by way of the bottom work roll chock to the bottom work roll; characterized in that the housing further includes a housing window that bears a force in the rolling direction acting on the top work roll, and the device further comprises third hydraulic cylinders (7-1, 7-2) provided to the top back up roll chock and each including a third piston rod that applies a decrease-bending force to the top work roll or that brings the top work roll into contact with the top back up roll to generate a roll balance force; and fourth hydraulic cylinders (7-3, 7-4) each including a fourth piston rod that applies a decrease-bending force to the bottom work roll.