A packet transmitting apparatus (401) capable of transmitting a copyright-protected content across an IP network includes: a transmission condition setting/managing unit (403) that extracts from inputted non-A/V data or A/V data at least one information of billing information, reproduction control information, copy control information for the A/V data, and packet output control information, and generate encryption mode information indicating an encryption mode which becomes a condition during transmission of the A/V data; an encrypted data generation unit (422) that encrypts inputted A/V data based on a transmission condition determined by combining input terminal information, data format information, and attribute information, and adds an encryption information header based on the encryption mode information and time-based discontinuity information to the encrypted A/V data so as to generate encrypted data; and a packetization unit (406) that generates a packet by adding a packet header and information representing a time-based discontinuity point to the generated encryption data.