To provide a pressure-resistant explosion-proof container in which a wireless circuit housed inside the pressure-resistant explosion-proof container can transmit and receive a high frequency signal, without installing an antenna outside.A pressure-resistant explosion-proof container includes a container made of metal, a slit functioning as an explosion-proof clearance that is formed by penetrating a wall surface of the container, and a cavity resonator that is provided in the container and in which an antenna is built that transmits and receives a high frequency signal by using the slit as a waveguide.