A transmitting device includes: (i) an encoding rate managing section which controls an encoding rate of an encoding rate altering section which alters the encoding rate; (ii) an error resilience managing section which controls error resilience of an error resilience adding section; and a channel conditions measurement section which measures channel conditions of a communications medium. The encoding rate managing section and the error resilience managing section calculates a transmission capacity of packets in accordance with the channel conditions having been measured by the channel conditions measurement section, and then performs control of encoding rate setting or error resilience setting in accordance with the calculated transmission capacity.