To suppress deterioration in transmission characteristics caused when signals having the same code are continued.

A monitor part 1a monitors a level of the signal to generate a monitor value. A level control part 1b performs level control of an input signal based on the monitor value. An output amplification part 1c amplifies and outputs the signal whose level has been controlled. A control part 1d manages/controls a transmitter operating state based on setting information. The control part 1d recognizes the time where the same code of the input signal is continued from a signal format notified by the setting information, and performs variable control of at least one of a monitor time constant which is response time between when the signal is input in the monitor part 1a and when the monitor value is generated, and a level setting time constant which is response time between when the monitor value is input in the level control part 1b and when the level control is executed according to the time where the same code is continued.