To improve both liquid-tightness and operability in a syringe and a fluid substance transfer tool for transferring a fluid substance. A plunger has a plunger body, and a plunger head integrally furnished at the distal end of the plunger body and adapted to slide along the inner wall surface of an outer tube while maintaining liquid-tightness. At the circumferential edge portion of the distal end of the plunger head, a ring-shaped elastic piece that elastically contacts the inner wall surface of the outer tube when the plunger has been inserted into the outer tube, and that has lower resistance with respect to the inner wall surface of the outer tube when the plunger is pulled as compared with when the plunger is pushed, extends towards the front. Thus, during reciprocating motion of the plunger, both liquid-tightness and operability of the syringe can be improved, even in cases in which the force to pull the plunger is weaker than the force to push the plunger.對於移送流動性物質用的注射器及流動性物質移送具,可提高液密性及操作性的雙方。滑閥,是具有:滑閥本體、及一體地設在此滑閥本體的先端且對於外筒的內壁面一邊液密性地保持一邊滑動的滑閥頭部。在滑閥頭部的先端周緣部中,在滑閥被插合於外筒內的狀態下與外筒的內壁面彈性地接觸,與滑閥被推壓時相比,滑閥被拉引時,對於外筒的內壁面的阻力值減少的環狀的彈性片是朝向前方被延設。由此,將滑閥往復動時,與將滑閥推壓的力相比,將滑閥拉引的力即使變弱的情況,也可以提高注射器的液密性及操作性的雙方。32‧‧‧滑閥33‧‧‧滑閥本體34‧‧‧滑閥頭部34a‧‧‧先端周緣部35‧‧‧彈性片36‧‧‧溝
