A display device comprising: a reception unit configured to receive transmission data from an image capturing device that is configured to: - perform an image capturing process with a predetermined cycle to create image capturing data in each frame or field, and - perform a transmission process of transmitting a transmission packet while adding a packet ID indicating a number of the transmission packet in one frame or one field of the image capturing data for each transmission; a display processing unit configured to perform a display process of creating a display signal for display from the transmission packet; a measurement unit configured to: - detect the transmission packet in which the packet ID indicates a specified number as a specified packet, wherein the specified packet is specified in advance, and - measure a reception timing of the specified packet, the reception timing being indicated by a specified packet ID detection timing signal; a determination unit configured to determine whether or not the specified packet is a retransmission packet; and a processing unit configured to perform a phase adjustment process of the display signal using a measurement result of the measurement unit which is obtained by measuring the reception timing of only the specified packet which is determined as not the retransmission packet by the determination unit among the specified packets, wherein the determination unit is configured to detect a change in a reception interval of the specified packet to determine whether the specified packet has been retransmitted. a reception unit configured to receive transmission data from an image capturing device that is configured to: - perform an image capturing process with a predetermined cycle to create image capturing data in each frame or field, and - perform a transmission process of transmitting a transmission packet while adding a packet ID indicating a number of the transmission packet in one frame or one field of the image capturing data for each transmission; - perform an image capturing process with a predetermined cycle to create image capturing data in each frame or field, and - perform a transmission process of transmitting a transmission packet while adding a packet ID indicating a number of the transmission packet in one frame or one field of the image capturing data for each transmission; a display processing unit configured to perform a display process of creating a display signal for display from the transmission packet; a measurement unit configured to: - detect the transmission packet in which the packet ID indicates a specified number as a specified packet, wherein the specified packet is specified in advance, and - measure a reception timing of the specified packet, the reception timing being indicated by a specified packet ID detection timing signal; - detect the transmission packet in which the packet ID indicates a specified number as a specified packet, wherein the specified packet is specified in advance, and - measure a reception timing of the specified packet, the reception timing being indicated by a specified packet ID detection timing signal; a determination unit configured to determine whether or not the specified packet is a retransmission packet; and a processing unit configured to perform a phase adjustment process of the display signal using a measurement result of the measurement unit which is obtained by measuring the reception timing of only the specified packet which is determined as not the retransmission packet by the determination unit among the specified packets, wherein the determination unit is configured to detect a change in a reception interval of the specified packet to determine whether the specified packet has been retransmitted.