Cavitation erosion is one of the most serious problems as regards hydraulic equipment. Vibratory and cavitating jet methods are the major test methods of cavitation erosion. The merits of the former are a compact apparatus and convenient to exchange test fluids. Therefore, they are in wide use. However, it is impossible to test brittle and coated specimens. Also, the rise in the temperature of fluids and thermal distortion of the vibrating horn are the demerits. Cavitation used in the latter is almost same as that in valves and restrictors in the hydraulic systems. The experimental results are in good agreement with those of field operations. However, high-pressure pumps and tanks are required and the total size of the apparatus is too large. In this study, we tested six types of metal specimens (made of aluminium alloy, superduralumin, high-strength brass, stainless steel, carbon steel and chrome-molybdenum steel), and clarified experimentally relationships of the test results between the vibratory and cavitating jet methods. The conclusions are as follows. 1) The eroded volumes of aluminium alloy are largest, and those of superduralumin, those of high-strength brass, in order, and the order agree of well with both test methods. 2) The surfaces are eroded uniformly and by ring-shaped for the vibratory and the cavitating jet methods, respectively, and these behaviors are independent on the materials of specimens. The eroded surfaces due to vibration is finer than those due to the cavitating jet. 3) Fatigue fracture, plastic deformation and striation are observed. Mainly, striation and plastic deformation are observed for the vibratory and cavitating jet methods, respectively. 4) The ratios of eroded volumes by the vibratory to cavitating jet methods become constants as the time proceeds, and the ratios are almost independent regarding the materials.