To provide a machine component with an IC tag affixed thereto, in which with the IC tag having an increased storage capacity, the IC tag can be mounted with no difficulty and, also, reading or writing of information from or in the IC tag, respectively, can be facilitated. A plurality of IC tags 2 are attached to a machine component, which forms a part of a rolling bearing assembly 1, or to a machine component and an accessory with division made therebetween. Those plural IC tags 2 have different information stored therein. Where the machine component is a retainer incorporated rolling bearing assembly 1, those plural IC tags are attached to a roller retainer 5 at respective locations symmetrical with each other about the axis O of rotation thereof.