Hydraulic testing method and device

In order to efficiently and economically achieve precise hydraulic testing of each test tube, even when there is a wide range of test tube sizes, a plurality of pressure-increasing cylinders (41) are used that are connected in parallel to the test tubes and have a gradually increasing pressure-increase ratio. A plurality of servo motor drive pumps (51) arranged in parallel are used as the drive source for the plurality of pressure-increasing cylinders (41). The plurality of servo motor drive pumps (51) are operated simultaneously until the output-side water pressure of the pressure-increasing cylinders (41) approaches the test pressure. Then the driving of all but one of the plurality of servo motor drive pumps (51) is stopped and the pressure is increased to the test pressure by using the remaining one servo motor drive pump (51). When boosting pressure, the plurality of pressure-increasing cylinders (41) are used in order, from the cylinder having the lowest pressure-increase ratio to the cylinder having th