The present invention provides a developer for electrophotography which is superior in property of build up of electrification and in charge stability even in environments of high temperature and high humidity or in an environment of low temperature and low humidity where it is difficult for a developer to retain its electrostatic charge performance, and which can provide an image free from fogging and decrease in density for a long term, that is, a developer for electrophotography containing composite oxide particles which include metal titanate particles containing titanium as a first metal atom and a second metal atom and containing therein 0.009 to 0.350% by weight of a third metal atom selected from the group consisting of the metal atoms belonging to Group 5A of the long form of the periodic table of elements.