A sample analyzer includes a marking unit containing a marker for marking a container containing a sample, and a controller for controlling the marking unit based on sample information. A sample analyzing method includes a) providing a container containing a sample, b) obtaining the sample from the container, c) detecting a signal from the obtained sample, d) analyzing the detected signal, e) determining whether marking the container is needed or not based on sample information; and f) automatically marking the container if marking is needed.