A conditional access broadcast system for realizing conditional access while maintaining the safety level is disclosed. A contract management device at a broadcast station side delivers a reception contract information containing at least a contract information for controlling decryption of encrypted contents information delivered from a broadcast station by broadcast and a reception device ID in correspondence, which is encrypted using a master key which is commonly provided with respect to all the broadcast reception devices. At each broadcast reception device, whether or not to give a channel key for decrypting the encrypted contents information to the decryption unit is controlled according to the contract information for own broadcast reception device which is acquired from the encrypted reception contract information.