A communications device connects one or more first lighting devices included in a first local network with one or more second lighting devices included in a second local network different from the first local network. The communications device includes a single semiconductor integrated circuit including: a first processing unit that wirelessly communicates with the one or more first lighting devices via a first communications protocol; a second processing unit that wirelessly communicates with the one or more second lighting devices via a second communications protocol different from the first communications protocol; and a control unit that switches between causing the first processing unit to wirelessly communicate with the one or more first lighting devices and causing the second processing unit to wirelessly communicate with the one or more second lighting devices.