PURPOSE: To provide such a tension panel for a postor that wrinkles, waves, or curls do not occur in the postor attached even if temperature, or humidity changes.

CONSTITUTION: This tension panel is equipped with a frame 2 and four retaining units 3 and 5 each one end of which is attached to each of four corners of the frame 2 and each other end of which retains each corner of a poster 4 through a spring 3. Each retaining unit 3 and 5 applies the tension with the spring 3 to the poster along a straight line which divides the inner angle of the postor 4 into 45° each.