To provide a gear pump capable of speedily supplying lubricating liquid to the inside of a bearing in simple constitution in the case when it is used under the environment where pressure on the suction side becomes higher than pressure on the discharge side.

It is possible to supply lubricating liquid to the inside of bearings 4, 5 in simple constitution even under a use condition where pressure on the suction side becomes higher than pressure on the discharge side as suction side lubricating grooves 12, 13 one ends of which are open to the suction side and other ends of which are extended along the bearings 4, 5 and are opened to end parts of shafts are provided in the bearings 4, 5 to support shafts of a gear, these suction side lubricating grooves 12, 13 are communicated to the discharge side, and after working liquid flows from a suction port 8 to the suction side lubricating grooves 12, 13 and lubricates the inside of the bearings 4, 5, it is discharged from a discharge port 9.