Sample analyzer

A sample analyzer (1) comprising: a sample preparing part (60) for preparing a measurement sample by mixing a reagent for measuring coagulation time with a blood sample; a light emitting part (50) for emitting light to the prepared measurement sample; a light receiving part (42, 82b) for obtaining optical information at a plurality of time points by receiving light of a plurality of wavelengths over time from the measurement sample irradiated by the light; a first measuring means (40) for measuring content of an interference substance in the measurement sample that interferes optical measurement of the measurement sample based on optical information obtained by the light receiving part (42) at a time point before the measurement sample indicates coagulation reaction; and a second measuring means (80) for measuring coagulation time of the measurement sample based on the optical information obtained by the light receiving part (82b).