The invention relates to the field of workpiece processing, and discloses an automatic oil immersion device. The automatic oil immersion device comprises a support frame (1), a workpiece placing box (3), a lead screw lifting machine (4) and a conveying trolley (5), wherein the two ends of the support frame (1) are respectively provided with a feeding area and a discharging area, and an oil storagetank (2) is arranged between the feeding area and the discharging area; the workpiece placing box (3) is used for placing workpieces, and the bottom of the workpiece placing box (3) is hollow; the lead screw lifting machine (4) is used for lifting or lowering the workpiece placing box (3); and the conveying trolley (5) is positioned at the top of the support frame (1), the lead screw lifting machine (4) is arranged on the conveying trolley (5), and the conveying trolley (5) is used for driving the workpiece placing box (3) to move between the feeding area and the discharging area along the top of the support frame (1).