PROBLEM TO BE SOLVED: To provide an aid for easily inserting a guide wire into each guide wire lumen of a catheter having a plurality of guide wire lumens.SOLUTION: An aid 10 for inserting a guide wire into a plurality of guide wire lumens of a catheter comprises a jig body 11 provided with slits 21, 23 linearly extending from one end region 12 to the other end region 13. The jig body is configured so that one end region is thick in a height direction, the other end region is thinner than one end region, the formation depth of the slit is deep in one end region, and the formation depth of the slit is shallow in the other end region. The slit in the other end region is an insertion guide groove for inserting a catheter sheath of the catheter along an extension direction of the slit. The catheter sheath is inserted to one end region, and an end part of a guide wire lumen is exposed in a visible state at a slit exit in one end region.SELECTED DRAWING: Figure 1
