PURPOSE: To support works stably with one device even under the condition that inner diameters of works are various by providing a work support device for supporting the work from inside of the work.

CONSTITUTION: Multiple flexible narrow members A, which can be bended to one direction, are located so that each longitudinal axis (a) thereof is nearly in parallel with a predetermined axis Y and that the tip Al of each member is bended outside of the predetermined axis Y in the radial direction, and each member A is moved in the Y axial direction by a driving means B. Progress direction of the tip part Al is deflected outward of the radial direction on one surface by a deflecting member C, and work W is supported without changing height and angle of the tip part.