To provide a circuit system for a gastric and enternal nutrition drip infusion set in which the an erroneous connection with a connecting element of the circuit for an infusion set used for a jugular venous line with each other is surely prevented.

This circuit system has first to third containers 11, 21 and 31 which are respectively connected through tubes to three ports of a Y-shaped pipe 4, a connecting end member for a circuit system for a gastric and enternal nutrition catheter connected to the first connector, a male connector for the circuit system for the gastric and enternal nutrition drip infusion set and which is interpolatively connectable with the second and third connection respectively and a lure nozzle for a shot injection syringe. The first connector is the male canter having an outer diametral taper having stepwise nodes on its outer periphery and is non-connectable to the male type connecting member having a 6/100 taper meeting ISO standards. The second and third connector are the female connectors having inner diametral tapers and are non-connectable to the male type connecting member having a lure taper meeting the ISO standards.