PURPOSE: To bring an arm for supporting and conveying a load and effecting a work into a compact containing shape during its no-use and to expand the arm to a given length during its use.

CONSTITUTION: A windable and containable arm made of a shape memory alloy is formed such that a shape memory alloy sheet 1 having a given length and formed in a helically wound flat shape at a low temperature phase and having a shape similar to that of a cylinder expanded at a high temperature phase is inserted in a tube 2 made of a thin plastic film having the one end where a hot fluid feed port 3 is formed and the other end where a high fluid discharge port 4 is formed. During use, hot fluid is fed in the tube 2 through the hot fluid feed port 3 to bring the shape memory alloy sheet 1 into a high temperature phase. After completion of use, the feed of the hot fluid is stopped to bring the hot fluid into a low temperature phase. The arm is useful to conveyance of articles and to a work.