A surgical tool insertion aid is provided which enables simultaneous use of multiple surgical tools, as well as the independent exchange of a surgical tool during surgery. A tubular surgical tool insertion aid 1 aids insertion of surgical tools 11 and 13 into the body, and includes: an inner tube 2 into which the surgical tools 11 and 13 are insertable, and which is insertable into the surgical tool insertion aid 1; and a plurality of guide members 3 which are extended in the axial direction from a distal end side to a proximal end side in the inner peripheral surface of the surgical tool insertion aid 1. The inner tube 2 includes, on the outer peripheral surface thereof, an engaging member 4 that engages with the guide member 3 to be made slidable.