A device for measuring the natural bending strength of a sheet material, and for measuring the bending strength of a creased or scored portion of the sheet material, and for dynamically analyzing such test results. The device has a rotatable clamp, a load sensor, a data processing unit, and a data displaying unit. The load sensor is positioned to directly contact the sheet material being held by the clamp. The clamp and sheet material can be rotated so that the sheet material presses against the load sensor, and the data processing unit will then determine the resistance force detected by the load sensor and will determine the amount of rotation associated with that force, and the resulting data are then processed, stored, and can be displayed as output data in a predetermined form.