Production cross sections of Rf isotopes in the Cm-248+O-18 reaction were measured at the beam energy range of 88.2 to 101.3 MeV by use of a gas-filled recoil ion separator. The excitation functions of (260)Rf, (261)Rfa, and (262)Rf were obtained together with those of spontaneously fissioning nuclides which have few-second half-lives and have been assigned to (261)Rf(b) and a longer-lived state of (262)Rf. The excitation function of few-second spontaneously fissioning nuclide exhibited the maximum cross section at the O-18 beam energy of 94.8 MeV. The shape of the excitation function was almost the same as that of (261)Rfa, whereas it was quite different from those of (260)Rf and (262)Rf. A few-second spontaneously fissioning nuclide previously reported as (261)Rfb and (262)Rf observed in Cm-248+O-18 reaction was identified as (261)Rf(b).