PURPOSE: To achieve long life by belting a shape memory alloy drive material on a pair of different size pulleys and mounting a heating device in one side of a straight part of the drive material and mounting a cooling device in the other side and using a belt shaped seamless TiNi shape memory alloy member as the drive material.

CONSTITUTION: A driving belt 1 is belted on for example, pulleys 2a and 2b each having diameter of 70mm and 50mm and the belt 1 is rotated to obtain power by cooling one of this belt 1 at 18°C a cool device 6 and heating the other of this belt 1 is by a heat device at 90°C. A seamless TiNi shape memory alloy member is used for the belt 1 as a drive material in this shape memory alloy heat engine. This seamless TiNi shape memory alloy member is manufactured by drilling the TiNi shape memory alloy solid billet by a discharge processing to make it cylindrical shaped and cutting it in a width of the belt and extending and rolling it from an inner peripheral side of the cylindrrical member.