Japanese Patent Laying-Open No. 2006-234785 (PTD 1) discloses an abnormality diagnosing apparatus for a rolling bearing. With this abnormality diagnosing apparatus, a frequency analysis of an electric signal from a vibration sensor is conducted and, based on a spectrum obtained from the frequency analysis, a reference value is calculated. A peak of the spectrum that is larger than the reference value is sampled. Then, a frequency between the peaks and a frequency component owing to damage to the bearing and calculated based on the rotational speed are compared and checked with each other. Based on the results of the check, whether an abnormality of the rolling bearing is present or not and where the abnormality is present are determined (see PTD 1).