This is the study on the vibration characteristics of the fuel-injection pump body. Recently, refinement of the fuel spray is necessary in order to reduce the toxic substance, which is included in automotive exhaust gas of diesel engine for the automobile. To jet diesel fuel in higher pressure is a method for spraying the fuel more minute into a cylinder. However, this method causes the increase in respect of engine vibration and torque nonuniformity. The fuel-injection pump body receives not only this engine vibration by the method but also impact tute by the high-pressure injection. As this result, the sufficient performance cannot be demonstrated because large vibration deformations occur at the body and the camshaft of the fuel-injection pump. The vibration characteristics of the fuel-injection pump, which can reduce these vibration deformations, are necessary in order to lead to the performance. In this study, the high-pressure fuel injection pump body with small vibration deformation is analyzed through a grasp of the vibration characteristics of a typical fuel-injection pump body. In this experiment, some impulse points and measuring points were set. It was confirmed that the vibration of the low-level mode had been generated to the fuel-injection pump body in the frequency range of engine noise to 2000 Hz. Under the experimental conditions, the calculation results agree well with the experimental results in the engineering. Through this theoretical analysis, it was confirmed that vibrational stress concentration of camshaft bearing should be improved and the vibration transmission route from the injection nozzle to the bottom of injection pump body should be changed.