The structural stability of bacteriorhodopsin (bR) solubilized with n-octyl--glucoside (OG) at various concentrations were evaluated and the effects on inter/intra molecular interaction were examined by comparison with the case of solubilization with Triton X-100 (TX). Solubilized bR with OG had the conditions occurred only thermal bleaching without photobleaching, whereas TX solubilized bR not occurred thermal bleaching but photobleaching. Under these conditions, OG solubilized bR showed symmetrical bilobed exciton band that indicate remain of protein-protein interaction in the visible region by circular dichroism (CD) measurements. On the other hands, that of bR solubilized with TX were broad positive bands that indicate the retention of intra-molecular local conformation. Thus the effect on inter/intra molecular interaction and tertiary structural stability of bR was remarkably different though both OG and TX are non-ionic detergents. It was also suggested that the stability of bR in the ground state required the retention of intra molecular interaction, and intermolecular interaction was necessary to keep bR in function stable, based on correlation between the kinetics of thermal/photo bleaching and visible CD. The CD spectra in visible region could be non-destructive indicator of structural stability of bR.