To provide carbon fiber felt that has light weight, high flexibility and good fire resistance and insulating material.

The felt is constituted with carbon fiber aggregate and a binder for connecting the carbon fibers of this aggregate wherein the binder substantially does not include resin binder and is constituted with a silicone compound (for example, organosiloxanes, silanes or the like) bearing reactive groups (for example, a hydrolyzable and condensible group) and insulating materials. This felt can be produced by applying a silicone compound bearing reactive groups to the carbon fiber aggregate and they are heated to allow the reactive groups on the silicone compound to effect condensation reaction with each other.