A transmitting apparatus is provided with a transmit buffer for each of N-number of services for which the length of encoding time is ni·T (i=1, 2, . . . , N). The transmit buffer has a first storage unit for storing a length ni·T (i=1, 2, . . . , N) of transmit data, and a second storage unit for storing a reference time length T of transmit data. The following operation is carried out on a per-service basis: a length ni·T of transmit data is stored in the transmit buffer in the lengths T at low speed; a length ni·T of transmit data, which has already been stored in the transmit buffer, is read out in burst fashion at high speed in parallel with storage of a succeeding length T of transmit data in the transmit buffer; and storage and read-out of ni·T lengths of transmit data are subsequently performed in parallel in similar fashion and the transmit data that has been read out is input to an encoding processor.