[Object] To provide a pressure detection device which can suppress sluggishness of a circulating liquid, decrease the manufacturing cost and the capacity of a liquid flow route, prevent an error due to a difference between separate peristaltically-actuated tubes or displacement detecting means, and detect pressure in the liquid flow route with higher accuracy. [Solution] A pressure detection device of a liquid flow route includes: displacement detecting means 18 that detects displacement of a peristaltically-actuated tube 1a in the radial direction pressure calculating means 20 that is able to calculate blood removal pressure based on the displacement of the peristaltically-actuated tube closed flow route forming means that is able to form a closed flow route which includes a portion at which the displacement detecting means 18 is disposed pressure changing means that is able to arbitrarily change the pressure in the closed flow route pressure detection means that is able to detect pressure change in the closed flow route and calibration curve acquiring means 26 that is able to produce and acquire a calibration curve with which the displacement detecting means 18 and the pressure calculating means 20 are calibrated by a relationship between the pressure change detected by the pressure detection means and a detection value of the displacement detecting means 18.【課題】流通させる液体の淀みを抑制することができるとともに、液体流路の製造コスト及び容量を低減させることができ、かつ、被しごきチューブ又は変位検出手段の個体差に基づく誤差を抑制することができ、液体流路の圧力をより精度よく検出させることができる圧力検出装置を提供する。【解決手段】被しごきチューブ1aの径方向の変位を検出する変位検出手段18と、その変位から脱血圧を算出し得る圧力算出手段20と、変位検出手段18の配設部位を含みつつ閉鎖流路を形成し得る閉鎖流路形成手段と、閉鎖流路内の圧力を任意に変化させ得る圧力変化手段と、閉鎖流路内の圧力変化を検出し得る圧力検出手段と、圧力検出手段で検出された圧力変化と変位検出手段18の検出値との関係により変位検出手段18及び圧力算出手段20の校正のための検量線を作成して取得し得る検量線取得手段26とを具備したものである。【選択図】図1
