To provide a vibration testing device capable of conducting tests of vibration that are close to the vibrations of actual vehicles, at low cost.

The present vibration testing device is equipped with an operating unit, a setting unit, a detection unit, and an adjusting unit. The operating unit gives vibration to vehicles by its displacement via an orbital unit. The setting unit outputs the command amplitude or the target value of displacement of the operating unit. The detecting unit detects the displacement of operating unit to output displacement signals of the displacement concerned. The adjusting unit outputs adjusted signals, making the operating unit to displace based on the displacement signals and the command amplitude. The setting unit computes power spectral density from acceleration during a predetermined time of dolly device from actual measurement, computes the displacement amplitude in a plurality of frequency intervals based on the power spectral density concerned, and determines the sinusoidal wave that uses the displacement amplitude concerned as the command amplitude.