A waist supporting back brace frame for a detachment type waist protecting belt to hold the vertebra region of a vertebra related patient is provided. The frame is comprised of two back rest frames, one power module, one puller, one string that is engaged and connects two parts (left and right) of the power module, and two set of broad bands. Each part of the power module is equipped with four pairs of string conveying mini rollers. Pluralities of gear teeth are developed on the surface of the string conveying mini rollers along the vertical axis thereof. Upper and lower corner of the teeth is rounded to minimize friction between the roller and the power module when a wearer put on the frame and fasten.
