The present invention efficiently suppresses a false defect and realizes reticle inspection where a defect can be detected with high detection sensitivity. In a reticle inspecting method, reticle inspection data generated based on reticle design data is captured. Also, drawing position accuracy measurement data of the reticle is captured to obtain a first correction amount for correcting a position accuracy component of the reticle. Based on the first correction amount, the inspection data is corrected. Based on the corrected inspection data, a defect on the reticle is detected.