An abnormality diagnosis system configured to perform abnormality diagnosis on equipment that performs operation repeating a fixed pattern, the abnormality diagnosis system comprising: a sampler configured to sample time series data indicating a state of the equipment, the time series data repeating a pattern corresponding to the fixed pattern; and a calculator configured to perform principal component analysis based on the time series data sampled by the sampler, and diagnose whether the equipment has an abnormality, wherein the calculator is configured to: perform first principal component analysis on one pattern in the time series data indicating the state, and perform first abnormality determination of whether there is an abnormality based on a result of the first principal component analysis; characterized in that the calculator is further configured to in the case where a result of the first abnormality determination is that there is an abnormality, perform second principal component analysis collectively on a plurality of patterns successive in time including the pattern subjected to the first principal component analysis in the time series data indicating the state, and perform second abnormality determination of whether there is an abnormality based on a result of the second principal component analysis; and in the case where a result of the second abnormality determination is that there is an abnormality, diagnose the equipment as having an abnormality. a sampler configured to sample time series data indicating a state of the equipment, the time series data repeating a pattern corresponding to the fixed pattern; and a calculator configured to perform principal component analysis based on the time series data sampled by the sampler, and diagnose whether the equipment has an abnormality, wherein the calculator is configured to: perform first principal component analysis on one pattern in the time series data indicating the state, and perform first abnormality determination of whether there is an abnormality based on a result of the first principal component analysis; characterized in that the calculator is further configured to in the case where a result of the first abnormality determination is that there is an abnormality, perform second principal component analysis collectively on a plurality of patterns successive in time including the pattern subjected to the first principal component analysis in the time series data indicating the state, and perform second abnormality determination of whether there is an abnormality based on a result of the second principal component analysis; and in the case where a result of the second abnormality determination is that there is an abnormality, diagnose the equipment as having an abnormality. perform first principal component analysis on one pattern in the time series data indicating the state, and perform first abnormality determination of whether there is an abnormality based on a result of the first principal component analysis; characterized in that the calculator is further configured to in the case where a result of the first abnormality determination is that there is an abnormality, perform second principal component analysis collectively on a plurality of patterns successive in time including the pattern subjected to the first principal component analysis in the time series data indicating the state, and perform second abnormality determination of whether there is an abnormality based on a result of the second principal component analysis; and in the case where a result of the second abnormality determination is that there is an abnormality, diagnose the equipment as having an abnormality. <EOS>