A sample analyzer comprising: a sample preparing section for preparing first and second measurement sample including reagent and sample; a first detector for detecting a predetermined component in the first measurement sample prepared by the sample preparing section; a second detector for detecting the predetermined component in the second measurement sample prepared by the sample preparing section; and a controller configured for performing operations, comprising: (a) controlling the first detector to detect the predetermined component in the first measurement sample prepared by the sample preparing section; (b) determining the reliability of the result detected by the first detector; (c) controlling the sample preparing section to prepare the second measurement sample from the same sample when the result has been determined to be unreliable; and (d) controlling the second detector to detect the predetermined component in the second measurement sample, is disclosed.