A communication device capable of preventing a failure in light emission control caused due to communication with a lighting device such as the master and the slave. The communication device is capable of connecting to an image pickup device and transmits a lighting instruction from the image pickup device to a lighting device through a communication unit capable of performing bidirectional communication. It is determined whether or not the lighting device is ready for lighting. The lighting device is prevented from transmitting information to the communication unit when the lighting device is ready for lighting.