A self-lubricating assembly for a linear driving device comprises an oil applying subassembly, an oil transmitting subassembly and an oil container. The oil transmitting subassembly transmits lubricating oil from the oil container to the oil applying subassembly, and the oil applying subassembly is driven by the linear driving device to perform lubricating action automatically. The oil container is provided for storing lubricating oil to prolong lubricating time of the linear driving device.