Abstract: A crimping device having a reciprocating driven member which is moved back and forth at a rear end of a tubular body inside, a cam which is coupled to a front end of the reciprocating driven member through a link and can be swung with a pin as its fulcrum point, a caulking arm which is in forced contact with the cam at a rear end roller and has a front end claw freely going in and out of a caulking concave portion located at a front end of a main body and is carried by a separate pin at its intermediate portion, a return spring which returns the reciprocating driven member to an ordinary rear end position, and a return spring which always presses the roller onto a cam surface of the cam, the cam surface having such a shape as to push up the roller when the reciprocating driven member is moved forward.