Viscous solutions of polymethylsilane (PMS) and polycarbosilane (PCS) mixed at various ratios were prepared and shaped into fiber farm by the dry-spinning method using benzene as solvent. The addition of PMS to PCS lowered onset temperature of the precursor fiber oxidation, and slightly increased the residual mass after pyrolysis. The fibers from the precursors containing PMS yielded the ceramic fibers after heat treatment at 1273 K without degradation and fusing, but they changed into crystalline fibers having thin amorphous layer on the surface after the heat treatment at 1673 K.