A flash device (200, 200A) adapted for use in an image capturing system including an image capturing device and at least one further flash device (200B, 200C), the flash device comprising: an interface for communicating with the image capturing device; wireless communication means for wirelessly communicating with said at least one further flash device (200B, 200C) of the image capturing system; input means for receiving a control signal from the image capturing device relating to said at least one further flash device (200B, 200C) of the image capturing system; and shift means for causing the wireless communication means to shift between operation modes including a default reception mode in which signals from said at least one further flash device can be received, a transmission mode in which signals are transmitted to outside and the reception of signals from said at least one further flash device (200B, 200C) is disabled, and a transmission-reception suspension mode in which both the transmission and reception of signals are disabled, wherein the control signal includes a notification signal of starting a flash sequence, and a flash instruction signal, said flash instruction signal causing the wireless communication means to transmit a flash command to said at least one further flash device (200B, 200C), wherein the shift means causes the wireless communication means to shift to the transmission-reception suspension mode after the input means receives the notification of starting the flash sequence and transmits it to the said at least one further flash device, wherein, in a case where the input means receives the flash instruction signal after shifting to the transmission-reception suspension mode, the shift means causes the wireless communication means to shift directly from said transmission-reception suspension mode to the transmission mode, wherein the wireless communication means is adapted to transmit the flash command to said at least one further flash device (200B, 200C) after shifting to the transmission mode. an interface for communicating with the image capturing device; wireless communication means for wirelessly communicating with said at least one further flash device (200B, 200C) of the image capturing system; input means for receiving a control signal from the image capturing device relating to said at least one further flash device (200B, 200C) of the image capturing system; and shift means for causing the wireless communication means to shift between operation modes including a default reception mode in which signals from said at least one further flash device can be received, a transmission mode in which signals are transmitted to outside and the reception of signals from said at least one further flash device (200B, 200C) is disabled, and a transmission-reception suspension mode in which both the transmission and reception of signals are disabled, wherein the control signal includes a notification signal of starting a flash sequence, and a flash instruction signal, said flash instruction signal causing the wireless communication means to transmit a flash command to said at least one further flash device (200B, 200C), wherein the shift means causes the wireless communication means to shift to the transmission-reception suspension mode after the input means receives the notification of starting the flash sequence and transmits it to the said at least one further flash device, wherein, in a case where the input means receives the flash instruction signal after shifting to the transmission-reception suspension mode, the shift means causes the wireless communication means to shift directly from said transmission-reception suspension mode to the transmission mode, wherein the wireless communication means is adapted to transmit the flash command to said at least one further flash device (200B, 200C) after shifting to the transmission mode.