The problem is to provide means for restraining hardening of silicone rubber. The silicone rubber composition of the present invention contains an antioxidant dispersed therein. In addition, the present invention provides a method for preparing the silicone rubber composition that includes: a step of mixing a silicone rubber precursor and the antioxidant and curing the obtained mixture or a step of wetting the silicone rubber with a liquid antioxidant. The present invention also provides a method of manufacturing a medical device, including: a step of incorporating into a medical device the silicone rubber composition obtained in the preparation method outlined above a step of seal packaging the obtained medical device and a step of irradiating the seal-packaged medical device with radiation.
