PURPOSE: To provide a working device for a pipe with a groove on its inside surface, by which a long pipe with a groove on its inside surface and with a high heat exchanging efficiency can be manufactured, also the defective insertion of the pipe does not occur, and the pipe with the groove on its inside surface and with satisfactory surface and shape can be manufactured.

CONSTITUTION: In a working device for a pipe with a groove on its inside surface, equipping with a form rolling part 1 consisting of plural balls 2 planetary-rotatable on the outer peripheral surface of the pipe to be worked and a groove plug inserted into the pipe in a position where the pipe is caught with the form rolling part 1, it is set that the diameter of the ball 2 is 4 to 17mm and a shortest distance between respectively adjacent balls 2 is 0.5 to 7mm.