When blood is collected using the blood collection device 1 of the present invention, the liquid L different from blood is filled in the flow path on the suction / discharge mechanism 5 side, and the liquid L filled in the flow path on the suction / discharge mechanism 5 side is filled. The gas G is sandwiched in the flow path between the blood and the blood to be collected, and the liquid L filled in the flow path on the suction / discharge mechanism 5 side is sucked and discharged during a waiting time between the collection and the next collection. The gas G is pushed / pulled by pushing / pulling 5 to control the movement of blood to be collected. In this way, the blood to be collected continues to move by pushing and pulling the liquid L / gas G by the suction / discharge mechanism 5 during the standby time, so that the blood to be collected does not solidify in the flow path, and the blood to be collected Solidification can be prevented.この発明の採血装置１を用いて血液を採取する際に、血液とは別の液体Ｌを吸引吐出機構５側の流路に満たし、吸引吐出機構５側の流路に満たされた当該液体Ｌと採取対象の血液との間に気体Ｇを流路内に挟み込み、採取と次の採取との間である待機時間に吸引吐出機構５側の流路に満たされた当該液体Ｌを吸引吐出機構５により押し引きすることにより気体Ｇを押し引きして、採取対象の血液を移動制御する。このように、待機時間に吸引吐出機構５により液体Ｌ・気体Ｇを押し引きすることで採取対象の血液が動き続けるので、採取対象の血液が流路内で固まることなく、採取対象の血液の凝固を防止することができる。
