Effects of hydrostatic pressure on the Raman spectra have been investigated for four kinds of 13-diketone crystals with hydrogen-bonded molecular chains. In all the crystals we studied, intense CO stretching Raman mode shows pressure-induced softening reflecting compression of the hydrogen bonds. Furthermore, application of pressure broadens the both C=O and C-O stretching modes and intensifies several specific vibrational bands. We ascribed these spectral changes to formation or growth of the kink-type defects of the hydrogen-bonded sequence.