A processing apparatus includes a processor configured to: compare a first index with a first reference value that has been determined for the first index, the first index indicating a receiving performance of a wireless signal that has been received by a receiving antenna from a medical device; perform switching to a first mode or a second mode based on a result of the comparing; and when the switching has been performed to the second mode, set a radiation direction of the receiving antenna toward a section in which a second index satisfies a condition relative to a second reference value that has been determined for the second index, from among a plurality of sections from which the receiving antenna receives the wireless signal, the second index indicating the receiving performance of the wireless signal that has been received.