An antenna driving apparatus drives an antenna by applying to the antenna a drive voltage having a rectangular waveform switching between a high voltage value and a low voltage value in a predetermined cycle. The antenna driving apparatus includes a high-voltage side switch, a low-voltage side switch, a duty ratio acquisition unit, a drive voltage application unit and a duty ratio switching unit. The duty ratio acquisition unit acquires a set value of a duty ratio as a time ratio at which the drive voltage is at the high voltage value in the rectangular waveform. The drive voltage application unit applies to the antenna the drive voltage by repeating execution of turning the high-voltage side switch into the nonconductive state. The duty ratio switching unit alternately executes switching of the duty ratio between a first duty ratio and a second duty ratio.