A bending apparatus has (a) a first manipulator which feeds a hollow metal blank of closed cross section in its lengthwise direction, (b) a second manipulator which supports a first support means disposed at a first position and a metal blank while feeding it, a heating means disposed at a second position downstream of the first position in the blank feed direction for heating all or part of the circumference of the blank, and a cooling means disposed at a third position downstream of the second position for cooling a portion of the heated blank, and (c) a third manipulator which constitutes a second support means disposed at a fourth position downstream of the third position in the feed direction of the blank and which moves two-dimensionally or three-dimensionally while supporting at least one location of the metal blank to bend the metal blank into a desired shape.