A gastrostomy catheter introducing device includes a puncturing device 1 including a body 6 having a tube 4 and a flange 5, and a puncturing needle 7 axially slidably held in the tube 4 of the body 6; and a gastric wall fixating and fistula expanding device 2 including an outer tube 9 to be inserted into the tube 4 of the puncturing device 1, a gastrostomy catheter guide member 10 held inside the outer tube 9, a clip 11 swingably attached to an inner end part of the gastrostomy catheter guide member 10, and a clip turning member 12 having one end connected to the clip 11 to turn the clip 11.