[en] The heat-resistant silicon carbide (SiC) fiber was formed from the precursor fiber of silicon containing organic polymer 'polycarbosilane (PCS)' by radiation curing technique. PCS fibers were irradiated in He atmosphere by 2MeV electron beam, then the fiber changed to non-melt fibers during the heat treatment for conversion from PCS fiber to SiC fiber. The SiC fibers, which contained less oxygen by the radiation curing of PCS fiber, showed high heat-resistance. The tensile strength and Young's modulus of SiC fiber containing oxygen of 0.4 % was 2.5 GPa and 280 GPa, respectively, after heat treatment at 1973 K (1700C) in Ar atmosphere, which is higher by 500 K than those of SiC fiber as 'Nicalon' which was formed from thermal oxidation curing of PCS fiber. (author)