Disclosed is an interlocking system between content player devices. The interlocking system includes: a first mobile device; a second mobile device, in which an interlocking program is installed, interlocked with the first mobile device, and configured to receive and execute one or more contents executed by the first mobile device, and a vehicle head unit, in which an interlocking program is installed, interlocked with the second mobile device, and configured to receive and execute the contents executed by the second mobile device.