A transmission convergence sublayer multiplex generating apparatus includes a TC layer calculating section, a TC layer information storing section for storing TC layer information in correspondence with each path, and an ATM layer information storing section for storing ATM layer information in correspondence with each path. The TC layer calculating section includes a section for, when receiving an ATM layer cell, storing the ATM layer cell in the ATM layer information storing section corresponding to a path number on the basis of header information of the ATM layer cell, and for, when receiving a TC layer information read request for each path through a control line, generating header error control information and scrambling the payload portion by time division multiplex processing using the ATM layer information of the corresponding path which is stored in the ATM layer information storing section to generate TC layer information, storing the TC layer information in the TC layer information storing section of the corresponding path, and outputting the TC layer information of the corresponding path to the TC layer information output line. A transmission convergence sublayer multiplex terminating apparatus is also disclosed.