It is one of the main subjects in tribology to systematize the wear theory. It is necessary to know the wear mode caused under the given condition by clarifying the various wear mechanisms. A lot of machines are operated in the lubricated condition. However, the wear mode diagram under the lubricated condition is not enough. In the present study, we aim to construct of the lubricated wear mode diagram for WJ2 which is the standard plane bearing material in a power plant. The sliding wear tests of WJ2 were carried out using a block-on-ring apparatus with various loads and sliding velocities. In order to classify wear modes, we investigated the relations among friction coefficient, worn surface, wear debris, specific wear amount of WJ2 and the minimum oil film thickness which were calculated from the EHL theory. As a result, the wear mode of WJ2 was classified into two types of large-scale adhesive wear and small-scale adhesive wear using the experimental result, and theoretical analyses.