A method of manufacturing a supporting structure includes disposing a supported member between a pair of opposed support walls, the support walls and the supported member having shaft holes formed coaxially through the support walls and the supported member respectively, inserting a shaft member through the shaft holes in the disposed state, the shaft member having two ends each having a peripheral portion circumferentially divided into a plurality of swaging portions continuous without discontinuity and swaging the swaging portions sequentially such that regions of the shaft member corresponding to the respective swaging portions are fixed in the shaft holes. The swaging portions include first swaging portions and second swaging portions, both of which are disposed so as to be paired at both radial sides of the shaft holes, respectively. A larger swage load is applied to each first swaging portion than to each second swaging portion.