A method for forming a silicon carbide film containing Si, C, O, H, and optionally N on a substrate placed in a reaction space, includes the steps of: introducing into the reaction space a precursor containing Si, C, O, and H and having at least one Si—O bond in its molecule; introducing into the reaction space an inert gas; applying RF power in the reaction space, wherein a ratio of a flow rate (sccm) of the inert gas to the RF power (W/cm2) is controlled at 30-850; and thereby depositing on the substrate a silicon carbide film containing Si, C, O, H, and optionally N.