We observed photo-induced conduction in silver- or gold-electroded silver metaphosphate glass by illumination from a mercury lamp. Photo-illumination caused photoelectron emission from the electrode surface. The silver or gold ions thus generated were neutralized by the electrons from the outside. Some of the electrons photo-generated were unable to escape the surface and caused charging, by which the conduction current through the glass was induced. Comparison was made with alumina ceramics in place of glass. (C) 2001 Elsevier Science B.V. All rights reserved.