Fundamental researches on complex hydrides are recently of great importance to develop practical hydrogen storage materials with higher gravimetric hydrogen densities than those of conventional materials. In this preliminary report, we discuss the correlation between B-H atomistic vibrations in [BH 4 ] - -anion and melting temperatures of MBH 4 (M=Li, Na, andK), on the basis of the experimental results combined the Raman spectroscopy and differential scanning calorimetry. Both the B-H stretching modes ν 1 and B-H bending modes ν 2 , decrease in the order of LiBH 4 >NaBH 4 >KBH 4 , except for ν 1 of LiBH 4 . On the other hand, the melting temperatures under hydrogen atmosphere as an index of hydrogen desorption (decomposition) temperatures decrease in the opposite order.