To smoothly and surely discharge intraabdominal retention liquid to the outside by coatingly attaching a porous clogging prevention cap composed of a porous material to an indwelling part as a clogging prevention means for a side hole directly opened to the abdominal cavity, in the intraabdominal indwelling catheter indwelling part.

The clogging prevention cap 1 provided in a tip opening part 3 and an indwelling part 2 having a side hole of an intraabdominal indwelling catheter used for the abdominal dialysis is formed of sponge and provided with a hole having an approximately same thickness as that of the catheter in one part of the long axis direction. This constitution allows the side hole in the indwelling part 2 directly opened to the abdominal cavity to gather the intraabdominal retention liquid from the opening part of the side hole via fine holes of the porous material from a wide range. This constitution can prevent the clogging without reducing the external discharge of the intraabdominal retention liquid and smoothly discharge it to the outside.