Photoelectron spectra of SinCm- cluster anions (1 less than or equal to n less than or equal to 7 and 1 less than or equal to m less than or equal to 5) were measured at the photon energies of 3.49 eV, by using a magnetic bottle electron spectrometer. The SinCm- clusters were produced either by a laser vaporization of a silicon-carbon mixed rod or by two laser vaporizations of carbon and silicon rods in a He carrier gas. The spectra of the SinC1- (3 less than or equal to n less than or equal to 7) clusters are similar to those of pure Si-n+1(-) clusters in the peak positions and their envelopes, which is attributed to the isovalent electronic structure of Si and C atoms as well as to the similar geometrical structure. In contrast, the similarity in the photoelectron spectra is not observed between C-m+1(-) and Si1Cm- (2 less than or equal to m less than or equal to 5) clusters, which is attributed to a change in their geometry; from chain to ring. These experimental conclusions are discussed with the results of our theoretical calculations.