An antenna drive apparatus applying an antenna drive voltage to an antenna from an H-bridge circuit including four switching elements to drive the antenna, includes: a switching mechanism to switch between a full-bridge state in which a differential voltage between a pulse voltage and a reverse pulse voltage reversed from the pulse voltage is applied to the antenna as the antenna drive voltage, and a half-bridge state in which the pulse voltage or the reverse pulse voltage is applied to the antenna as the antenna drive voltage; and a control mechanism to control the switching mechanism so that the frequency of the full-bridge state per unit time during an initial period of driving of the antenna in a transmission period for transmitting a transmission signal by the antenna becomes higher than that during the subsequent period in the transmission period.