A long-standing issue, i.e., whether the molecule of trans-stilbene is distorted around the central C=C bond and/or the C-phenyl bond in solution, is examined by performing density functional calculations of the Raman intensity of the in-phase CH out-of-plane wag of the central CH=CH group. Dependencies of the Raman intensity of the said mode upon the torsional angles around the central C=C and C-phenyl bonds are calculated. Not only the normal species of trans-stilbene but also two isotope-labeled species, (C6H5CH)-C-13=(CHC6H5)-C-13 and C6H5CD=CDC6H5, are treated. Comparisons of the calculated results with the observed spectra show that the trans-stilbene molecule is distorted in solution. The ranges of distortion around the central C=C and C-phenyl bonds are estimated to be 2.5-4.0degrees and 8.0-12.0degrees, respectively, from the planar arrangement around the respective bonds.