The invention relates to an automatic lubricating device and an automatic lubricating method. The automatic lubricating device comprises a detection part, an electric control part, a drive part and a jetting part. The detection part is used for detecting chain wheels. The detection part is electrically connected with the electric control part and sends a detection signal to the electric control part. The electric control part is electrically connected with the drive part and sends a control signal to the drive part. The drive part is connected to the jetting part and used for driving the jetting part to jet lubricating oil to the chain wheels. By means of the automatic lubricating device and the automatic lubricating method, jetting of the lubricating oil can be automatically completed, manual operation is not needed, the problems that consumed time caused by manual lubrication is long, the workload is large, and efficiency is low are solved, and the labor intensity of lubricating personnel is greatly lowered.