The present invention discloses a flow cytometric apparatus comprising a flow chamber to be passed through by a sample in a row in sequence, a sample storage means for metering and storing the sample, a sample syringe for driving the sample into the flow chamber, a syringe-type injection-suction means comprising a sheath liquid syringe and a liquid-path switching means connected with it, and a control unit for controlling the operations of the sample syringe and the syringe-type the injection-suction means. In a sample charging stage, the injection-suction means feeds the sample into the sample storage means so that the sample is temporarily stored in it in a ready-to-use state, and in a sheath-liquid injection stage, the injection-suction means feeds the sheath liquid into the flow chamber to form a sheath flow. A flow cytometric method performed by the flow cytometric apparatus is also disclosed.