Assembly device for stacked ring

When ring components 4 of layers to assemble a laminated ring 3 are unloaded from a component storage facility 10, a computer 13 generates lamination combinatorial data representing a combination of ring components of layers. A target frequency distribution of circumferential length values of ring components 4 of each layer is established, and lamination combinatorial data including ring components of a class where an error of an actual inventory frequency with respect to a target frequency is large are selected in a layer where an error between the target frequency distribution and an actual inventory frequency distribution is maximum. Ring components 4 of all layers corresponding to the selected lamination combinatorial data are unloaded from the component storage facility 10. A distribution of size data of the ring components 4 of each layer in the component storage facility 10 is thus continuously maintained in a state capable of assembling more laminated rings 4, and the stable mass-productivity of laminated rings 3 is continuously achieved.