The utility model discloses an automatic lubricating device for a dust cover of a machine tool. The automatic lubricating device comprises a machine tool body (1), a workbench (2) and a dust cover (3), wherein a stay bar (11) is arranged on one side of the machine tool body (1); an oil pipe (12) is arranged on the stay bar (11) in the axially horizontal direction of the machine tool body (1), and connected with an oil tank (6); a plurality of lubricating spray guns (13) are uniformly arranged at the lower end on the outer side of the oil pipe (12); an electromagnetic valve (5) is also arranged above the stay bar (11); each lubricating spray gun (13) is connected with the electromagnetic valve (5); the electromagnetic valve (5) is connected with a control device. A plurality of lubricating spray guns (13) are arranged above the dust cover (3), so that the dust cover (3) can be lubricated in a way of full coverage or point to point; the automatic lubricating device is simple in structure, convenient and fast to operate, and high in production safety; through the adoption of the automatic lubricating device, the dust cover (3) can be uniformly lubricated, and the service life of the dust cover can be effectively prolonged.