The invention provides an automatic oil recharging device, and relates to an industrial lubricant injecting and recharging device. The automatic oil recharging device comprises an upper oil storage cup and a lower oil storage cup. Spare oil quantity scales are marked on the outer wall of the upper oil storage cup. A guiding rod is arranged inside the upper oil storage cup. A conical plug, a conical compression spring and a compression spring base are arranged at the portion, at the lower end of the guiding rod, inside the lower oil storage cup. An oil outlet is formed in the left side of the lower oil storage cup. A pressure balancing pipe is installed on the right side of the lower oil storage cup. Circular oil level inspection windows are formed in the front side and the rear side of the lower oil storage cup. Due to the adoption of the technical scheme, compared with the prior art, the automatic oil recharging device has the advantages that the visual area is large, oil levels are clear, the structure is exquisite, the sealing performance is good, the appearance is attractive and elegant, the lower oil storage cup is not prone to aging, and is not easily discolored or broken, the mechanical strength is high, and the threaded strength is high.