A receiving device that receives a signal in a receiving antenna. The receiving device includes a gain controller that adjusts a gain in the receiving device in response to information related to power of the signal, and a signal detector that determines whether, within a predetermined period after the information related to the power of the signal exceeds a first threshold value, the information related to the power of the signal exceeds a second threshold value which is larger than the first threshold value. The gain controller adjusts a search range of the gain in the receiving device based on a determination result of the signal detector with respect to the information related to the power of the signal.