A method of and an apparatus for diagnosis of the operating conditions of a bearing wherein pressures of a film of oil formed on a sliding surface of the bearing journalling a rotary shaft are detected at a plurality of points on the sliding surface, and the pressure differential between the pressures of the oil film detected at the plurality of points is calculated. The deflection of the bearing with respect to the rotary shaft is calculated based on the calculated oil pressure film pressure differential, so that the operating conditions of the bearing are judged based on the deflection thereof.