The　objectives　of　this　paper　are　to　analyze　the　concept　of　academic　library　effectivenesscommonly　held　by　Japanese　librarians　and　to　compare　it　with　its　equivalents　revealed　byprecedent　studies　in　the　U．S．　and　New　Zealand．　Questionnaires　were　mailed　to　Japaneseacademic　librarians　in　September　1996．　ln　the　first　phase　of　this　mail　survey，　called　‘preferencesurvey’，　respondents　were　asked　to　indicate　how　important　each　of　100　indicators　was　forevaluating　academic　libraries　in　generaL　ln　the　second　phase，　so－called　‘performance　survey’，they　were　requested　to　assess　how　well　their　own　libraries　performed　in　terms　of　scope　eachindicator　dealt　with．　　　It　was　found　that　the　most　important　criterion　for　Japanese　librarians　was　whether　or　nota　library　sufficiently　supported　its　users’　research　and　educational　activities　and　that　the　mosthighly　valued　indicator　was　how　well　a　library　maintained　the　document　delivery　system　tosupply　its　users　with　materials　not　owned　by　the　library．　According　to　the　orthogonal　factoranalysis　of　the　responses　obtained　by　the　survey　thirteen　factors　were　extracted　in　thepreference　survey　and　eleven　in　the　performance　survey．　Those　factors　are　regarded　toconstitute　the　dimensions　of　Japanese　academic　library　effectiveness．