An infusion set comprising a first, a second and optionally one or more other caps , each for installation on a spike or a connector for connection with an intravenous drip needle, arranged at which there is an opening configured so as to not allow passage therethrough of solid or liquid but so as to allow passage therethrough of gas at the interior of the cap, a hydrophobic filter being arranged at a location inward from where the tip of the spike or the connector for connection with the intravenous drip needle is inserted at the interior of the cap by way of an insertion port for the spike or the connector for connection with the intravenous drip needle, and a lid at the exterior of said opening for closing said opening; a first, a second and optionally one or more other spikes ; a first, a second, a third and optionally one or more other three-way stopcocks , each having a primary tubing downstream branch connector equipped with a mechanism that connects in such fashion as to permit rotation about primary tubing as axis; a first, a second and a third male connector ; a drip chamber ; a roller clamp ; a connector for connection with the intravenous drip needle; first, second, third, fourth, fifth, sixth and optionally one or more other infusion tubing ; a first, a second, a third and optionally one or more other shutoff clamps , each for pressing on and opening and/or closing a flow path within the infusion tubing; and an optional filter bag ; wherein the first spike is provided at an upstream-most location of the first infusion tubing in the infusion set, the first spike being connected to one end of the first infusion tubing equipped with the first shutoff clamp , the other end of the first infusion tubing being connected to a primary tubing upstream branch connector of the first three-way stopcock , and connected to a secondary tubing branch connector at the first three-way stopcock there is one end of the second infusion tubing equipped with the second shutoff clamp , and the second spike covered with the first cap at the other end of the second infusion tubing, and further connected to a primary tubing downstream branch connector of the first three-way stopcock there is or are optionally the one or more other three-way stopcocks , connected to one end of the other infusion tubing, equipped with the other shutoff clamps and connected to the other spikes covered with the other caps , at secondary tubing branch connectors ; wherein the first male connector is further connected to a primary tubing downstream branch connector of that three-way stopcock which, among the first three-way stopcock and the other three-way stopcocks is disposed at a most downstream location, one end of the third infusion tubing equipped with the third shutoff clamp being further connected to the first male connector , and the drip chamber being connected to the other end of the third infusion tubing , the drip chamber being connected to one end of the fourth infusion tubing on which the roller clamp is installed, the other end of the fourth infusion tubing being connected to a primary tubing upstream branch connector of the second three-way stopcock , a primary tubing downstream branch connector of the second three-way stopcock being connected to the second male connector , one end of the fifth infusion tubing being further connected to the second male connector , and connected to the other end of the fifth infusion tubing there is a primary tubing upstream branch connector of the third three-way stopcock , a primary tubing downstream branch connector of the third three-way stopcock being connected to the third male connector , one end of the sixth infusion tubing being further connected to the third male connector , and the connector covered with the second cap being connected to the other end of the sixth infusion tubing . <EOS>