To provide a method and a device to assemble a coil spring to simplify a process to assemble a coil spring to a substance to be assembled without falling and reduce a manufacturing cost.

The body of a stick type ignition coil 10 is held in a specified position by using a holding means, not shown, and under-mentioned operation is performed based on information of a control part 9. A coil-winding outer diameter is surrounded such that the central axes of a coil spring 15 and an inlet part 11a are caused to coincide with each other by guide parts 6a and 6b and through drive of drive motors 7 and 8, the other end of the coil spring 15 is grasped by a press rod part 4 having a chuck claw 5 and movement in the direction of a containing space 16 and rotation in the winding direction of the coil spring 15 are effected. By this constitution, reduces the winding outer diameter while a large diameter part 15a being one end of the coil spring 15 makes pressure contact with a taper surface 17a, and the large diameter part is decreased in size lower than an inside diameter of the inlet part 11a and contained in a housing space 16.