A tire assembly includes a tire for mounting on a vehicle, an elastic body disposed on an inner side of the tire, and a power generation body disposed between an inner surface of the tire and the elastic body. The power generation body includes a first member and a second member. The first member has a first insulating film forming a first surface. The second member has a second insulating film forming a second surface that faces the first surface and contacts the first surface. The elastic body biases the power generation body toward the inner surface of the tire.