Disclosed herein are a dual-mode device operating in a visible light communications mode and a wireless network communications mode, and a method performed by the device. The visible light communications device includes a wireless network communications unit including a fixed identifier and performing communications based on a wireless protocol, a visible light transmitting unit transmitting the fixed identifier using a visible light communications protocol, and a controller (control unit) controlling the visible light transmitting unit so that it selectively transmits the fixed identifier using the visible light communications protocol depending on whether the wireless network communications unit is connected to a wireless network.