To provide a fluorine-containing rubber composition capable of forming a vulcanized molded product excellent in performance, even when exposed to plasma under a high load.

The fluorine rubber composition contains 0.7-2.4 pts.wt. polyfunctional unsaturated compound co-crosslinking agent and 0.3-1.0 pt.wt. organic peroxide per 100 pts.wt. fluorine rubber which has a fluorine content of 68 wt.% and can be subjected to peroxide crosslinking. The vulcanized molded product obtained from the fluorine rubber composition is excellent in resistance against O2 plasma treatment and particularly excellent in crack resistance when exposed to plasma under a high load. If the vulcanized molded product is a sealing, it gives required values for normal-state physical properties and compression set. The vulcanized molded product having such properties can be suitably used as components of an apparatus for manufacturing a semiconductor or a liquid crystal, e.g. a sealing, a conveying roller, etc.