Electric-field-induced change in fluorescence lifetime and pre-exponential factor has been measured for each fluorescence component of pyrene doped in a polymer film at a high concentration. Based on the results, the origin both of the field-induced quenching of structured fluorescence with a peak at similar to380 nm and broad excimer fluorescence with a peak at similar to470 nm and of the field-induced enhancement of another excimer fluorescence with a peak at similar to415 nm is discussed. (C) 2004 Elsevier B.V. All rights reserved.