An encrypted packet processing device capable of realizing a predetermined classification process according to a data type while reducing the burden on a processing device in a communication environment in which encrypted packets of different data types exist. A block specifying section specifies a location, in which information necessary for a priority level determination process by a priority level determination section is stored, in an encrypted packet. A specified block decryption section decrypts only a block specified by the block specifying section, and extracts the information necessary for the priority level determination process. The priority level determination section searches a priority level information database using the information extracted by the specified block decryption section as a key, and determines a priority level of the packet.