Small amplitude vibrations which are hardly observable by the normal time average method can easily be detected as a slight color valiation of the reconstructed image and the phase of vibration can be determined if light of two wavelengths is used and the phase of the reference wave is modulated in recording a hologram of a vibrating object. Colored reconstructed images of a vibrating disk are shown which have been obtained by using a He-Ne laser and an Ar-ion laser as light sources. The color variation of the image is examined and the procedure for determining the phase of vibration is discussed.