A vehicle image data transmission device that transmits image data obtained by capturing an image of a vehicle exterior to a management center managing travel information of vehicles includes an on-vehicle communication device and a communication controller. The communication controller is configured to transmit image data of the vehicle exterior recorded in a record device to the on-vehicle communication device through the internal network when a communication load of the internal network is less than a first predetermined value. The on-vehicle communication device includes a memory storing image data received from the communication controller and is configured to transmit image data stored in the memory to the management center through a vehicle external network when a communication load of the external network is less than a second predetermined value.