The S-1-S-0 electronic spectra of jet-cooled 5-phenyltropolone were measured to elucidate the features of phenyl torsion and its effect on intramolecular proton transfer. Several bands in the fluorescence excitation spectra were assigned to phenyl torsion and other low-frequency modes with the aid of the ab initio calculation. The torsional potential energy function was investigated with the one-dimensional torsional potential function analysis for the S-0 state. Presence of significant potential barriers due to the large H-atom steric repulsion between the phenyl ring and the tropolone ring were anticipated at the torsional angle phi = 0 degrees in both the S-0 and S-1 states. It was suggested that the large steric repulsion significantly influenced both phenyl torsion and proton transfer.