Microcrystals of In2S3 were formed on sintered In2O3 pellets by sulfurizing in H2S atmosphere. The flat band potential of compound In2S3\In2O3 electrodes was evaluated as - 1.0 V vs Ag\AgCl in 1 M KOH, 1 M Na2S, 10(-2) M S. Significantly enhanced photocurrent was observed on compound In2S3\In2O3 electrodes with a lower degree of sulfurization to that of compound In2S3\In2O3 electrodes with higher degree of sulfurization. Photocurrent generation of compound In2S3\In2O3 electrodes was explained from the viewpoint of semiconductor sensitization. (C) 2000 Elsevier Science B.V. All rights reserved.