Leveler equipment for flattening sheet material, characterized by comprising: a leveler body for flattening the sheet material, the leveler body including a pressing mechanism (14a, 14b) and a housing; a first roll cassette including upper and lower sets of roller-leveler leveling rolls (22, 26), the first roll cassette being configured to be able to be attached to and detached from the leveler body; and a second roll cassette including upper and lower sets of tension-leveler leveling rolls (32, 36), the second roll cassette being configured to be able to be attached to and detached from the leveler body, wherein: the first roll cassette and the second roll cassette are interchangeable; a roller leveler is formed when the first roll cassette is attached to the leveler body; a tension leveler is formed when the second roll cassette is attached to the leveler body; and the lever equipment further comprises a pair of bridle roll units (40a, 40b) provided on an entry side and a delivery side of the leveler body and each having bridle rolls (41, 42,43), and characterized by a controller configured to, when the roller leveler is formed, control the leveler equipment so as to flatten the sheet material by causing the pressing mechanism (14a, 14b) to apply pressing force to the sheet material via the upper, and lower sets of reoller-leveler leveling rolls (22, 26) in a state where the sheet material is passed between the upper and lower sets of roller-leveler leveling rolls (22, 26) of the first roll cassette without applying tensile force to the sheet material via the bridle rolls (41, 42, 43), and configured to, when the tension leveler is formed, control the leveler equipment so as to flatten the sheet material by causing the pressing mechanism (14a, 14b) to apply pressing force to the sheet maerial via the upper and lower sets of tension-leveler leveling rolls (32, 36) in a state where the sheet material is passed between the upper and lower sets of tension-leveler leveling rolls (32, 36) of the second roll cassette while applying tensile force to the sheet material via the bridle rolls (41, 42, 43). a leveler body for flattening the sheet material, the leveler body including a pressing mechanism (14a, 14b) and a housing; a first roll cassette including upper and lower sets of roller-leveler leveling rolls (22, 26), the first roll cassette being configured to be able to be attached to and detached from the leveler body; and a second roll cassette including upper and lower sets of tension-leveler leveling rolls (32, 36), the second roll cassette being configured to be able to be attached to and detached from the leveler body, wherein: the first roll cassette and the second roll cassette are interchangeable; a roller leveler is formed when the first roll cassette is attached to the leveler body; a tension leveler is formed when the second roll cassette is attached to the leveler body; and the lever equipment further comprises a pair of bridle roll units (40a, 40b) provided on an entry side and a delivery side of the leveler body and each having bridle rolls (41, 42,43), and characterized by a controller configured to, when the roller leveler is formed, control the leveler equipment so as to flatten the sheet material by causing the pressing mechanism (14a, 14b) to apply pressing force to the sheet material via the upper, and lower sets of reoller-leveler leveling rolls (22, 26) in a state where the sheet material is passed between the upper and lower sets of roller-leveler leveling rolls (22, 26) of the first roll cassette without applying tensile force to the sheet material via the bridle rolls (41, 42, 43), and configured to, when the tension leveler is formed, control the leveler equipment so as to flatten the sheet material by causing the pressing mechanism (14a, 14b) to apply pressing force to the sheet maerial via the upper and lower sets of tension-leveler leveling rolls (32, 36) in a state where the sheet material is passed between the upper and lower sets of tension-leveler leveling rolls (32, 36) of the second roll cassette while applying tensile force to the sheet material via the bridle rolls (41, 42, 43). the first roll cassette and the second roll cassette are interchangeable; a roller leveler is formed when the first roll cassette is attached to the leveler body; a tension leveler is formed when the second roll cassette is attached to the leveler body; and the lever equipment further comprises a pair of bridle roll units (40a, 40b) provided on an entry side and a delivery side of the leveler body and each having bridle rolls (41, 42,43), and characterized by a controller configured to, when the roller leveler is formed, control the leveler equipment so as to flatten the sheet material by causing the pressing mechanism (14a, 14b) to apply pressing force to the sheet material via the upper, and lower sets of reoller-leveler leveling rolls (22, 26) in a state where the sheet material is passed between the upper and lower sets of roller-leveler leveling rolls (22, 26) of the first roll cassette without applying tensile force to the sheet material via the bridle rolls (41, 42, 43), and configured to, when the tension leveler is formed, control the leveler equipment so as to flatten the sheet material by causing the pressing mechanism (14a, 14b) to apply pressing force to the sheet maerial via the upper and lower sets of tension-leveler leveling rolls (32, 36) in a state where the sheet material is passed between the upper and lower sets of tension-leveler leveling rolls (32, 36) of the second roll cassette while applying tensile force to the sheet material via the bridle rolls (41, 42, 43).