PURPOSE: To provide the title composition giving mild lily-of-the-valley-toned aroma in combination with green note, having both strong diffusivity and aroma retentivity, also highly harmonizing with any perfume material, containing m-t-butyl-α-methyl dihydrocinnamaldehyde.

CONSTITUTION: For example, m-t-butyl benzaldehyde and propionaldehyde are put to aldol condensation in the presence of an alkali condensation agent, and the resultant m-t-butyl-α-methyl cinnamaldehyde is subjected to catalytic addition to prepare m-t-butyl-α-methyl dihydrocinnamaldehyde. The objective perfume composition contains ca.0.1-95 (pref. ca.1-20)wt.% of this cinnamaldehyde.