The thin film obtained by the vacuum vapor deposition of cyanine dye (3, 3'-diethyl-2, 2'-thiacarbocyanine iodide), showed H (H-aggregation) mainly. This film transformed to the mixture of D (Dimeric aggregation) and M (Monomeric molecule) state by the acidic gas treatment. These mixture revert to H by the treatment of ammonia gas or heating. These phenomena were found to be reverse. The fluorescence intensity and photoconductivity of H are superior to those of the mixture state. The aggregate formation give an important effect on the photoconduction in solid. The effectively transfer of carrier will be occurred by the forming of H. The dark current of these various aggregation is not affected by the surrounding condition in vacuum and dry air. On the other hand, the photocurrent of H decreases in dry air, but not be effect for the mixture state.