Abstract: A gear bearing structure for an external gear pump includes a driving gear and the driven gear accommodated rotatably in a pump body of the external gear pump, an inlet chamber formed on one side of a mesh portion of the driving gear and the driven gear, an outlet chamber formed on the other side of the mesh portion, a hollow cylindrical bushing for holding a rotational shaft of the driving gear or the driven gear with a lubricating liquid film formed between itself and the rotational shaft, and a ring plate spring disposed between the pump body and the bushing to urge the bushing so as to slidably contact with a side face of the one of the driving gear and the driven gear.