The amount of carbon fiber-reinforced plastic (CFRP) used in automobiles and other products because of its lightness and strength is expected to increase year on year. Thus, low-cost, low-energy recycling technology will be required to recover carbon fiber from waste CFRP. Because fiber length is reported to decrease with each recycling, resulting in lowered performance, the present study investigated the effect of repeated recycling on the properties of carbon fiber recovered in a two-step thermal process of carbonization and calcination. it was found that fiber length decreased after the first recycling but scarcely changed after the second and third times, and that tensile strength decreased exponentially with repeated recycling.