A manual hydraulic pump includes a cylinder block 10 and an end block 8. The rear end of the cylinder block 10 and the end block 8 defines an end space 21 between them. The cylinder block 10 has cylinders 13 and oil passages 23. Each oil passage 23 extends between the rear end of one of the cylinders 13 and the end space 21. The end block 8 has a pair of cylindrical holes 27 opening into the end space 21. The end block 8 also has a pair of inlet/outlet ports 25 each communicating with the outside of the pump and one of the cylindrical holes 27. A distributing valve 22 is put in the end space 21 and spring-biased into compressive contact with the rear end of the cylinder block 10. The distributing valve 22 substantially takes the form of a disc and has a thickness smaller than the distance between the adjacent ends of the blocks 10 and 8. The distributing valve 22 has a pair of arcuate ports 22a formed on its front side. The arcuate ports 22a can communicate selectively with the oil passages 23 of the cylinder block 10 when this block turns. The distributing valve 22 also has a pair of cylindrical holes 22c formed on its rear side, each of which communicates with one of the arcuate ports 22a. A pair of pressing pistons 31 each include a rear cylindrical part 31a and a front cylindrical part 31b, which is smaller in diameter than the rear cylindrical part. The rear cylindrical part 31a is in axially slidable engagement with one of the cylindrical holes 27 of the end block 8, with an O-ring 33 interposed between this part and this block. The front cylindrical part 31b is in axially slidable engagement with one of the cylindrical holes 22c of the distributing valve 22, with an O-ring 32 interposed between this part and the valve. Each pressing piston 31 has an axial bore 31c cut through it.