A protector (1) includes a support member (18) mounted on a needle assembly (14) having a needle body (15), an outer cover member (36) mounted tiltably toward the needle body (15) by arms (42) rotatably supported on the support member ( 18), and an inner cover member (38) provided inside the outer cover member (36). The outer cover member (36) includes a tubular body (44) having an axially-extending needle slit (46) into which the needle body (15) is inserted. The inner cover member (38) includes a circulararc tubular body (51). The circular-arc tubular body (51) interlocks with the needle assembly (14) when the needle body (15) is inserted into the needle slit (46) by tilting the outer cover member (36), whereby the circular-arc tubular body (51) rotates while slidingly contacts on an inner surface of the tubular body (44). The circular-arc tubular body (51) has such a circular-arc cross section that the circular-arc tubular body (51) opens at least a portion facing the needle slit (46) when in an open position with respect to the tubular body (44) and that it closes the needle slit (46) when in a closed position.一種保護體(1)，具備裝在備有針本體(15)之針組裝件(14)上之支持部件(18)；與手臂(42)由支持部件(18)軸向支撐，朝針本體(15)之方向設置成可傾動之外蓋部件(36)；以及裝在外蓋部件(36)內側之內蓋部件(38)。外蓋部件(36)備有筒體(44)，此筒體(44)上設有能使針本體(15)插通，朝軸方向延伸之針切痕(46)。內蓋部件(38)備有當外蓋部件(36)因傾動而使針本體(15)插入針切痕(46)之時，能與針組裝件(14)連動，而與筒體(44)之內面摺動旋轉之圓弧柱體(51)。圓弧柱體(51)之形狀為剖面圓弧狀，此圓弧柱體(51)在對筒體(44)之開放位置上至少其面向針切痕(46)之處為開口，在封閉位置上能將針切痕(46)封閉。
