A transmission device according to the disclosure includes a power supply section, a first transmitter, and a controller. The power supply section includes a voltage generator that generates a power supply voltage, and a load section configured to be able to change a load current at the voltage generator. The first transmitter has a first operation mode and a second operation mode, and transmits a first signal on the basis of the power supply voltage. The controller controls an operation of the load section when an operation mode of the first transmitter transitions between the first operation mode and the second operation mode.