A kit comprising an cup assembly for an artificial hip joint, the kit including: an acetabular cup comprising a seating recess, a female taper formed on an inner wall, a plurality of protrusion recesses formed to communicate with the seating recess and disposed along the circumferential direction of the acetabular cup, and a plurality of insertion recesses formed inside the plurality of the protrusion recesses; and a bearing (200; 300) comprising a polyethylene bearing made of polyethylene material, the polyethylene bearing comprising an outer circumference having a male taper, a plurality of protrusions disposed along the circumferential direction of the polyethylene bearing and protruding in the radial direction, and a plurality of insertion protruding portions each formed on the outer portion of each of the protrusions and protruding on the outer portion of each of the protrusions,, and comprising a ceramic bearing made of a ceramic material, which ceramic bearing comprises a male taper formed on the lower portion of the ceramic bearing 300, wherein when the polyethylene bearing is engaged with the acetabular cup, the male taper of the polyethylene bearing is engaged with the female taper of the acetabular cup, and when the ceramic bearing is with the acetabular cup, the male taper of the ceramic bearing is engaged with the female taper of the acetabular cup, characterised in that the acetabular cup assembly is adapted such that when the polyethylene berning is engaged with the acetablular cup, each protrusion of the polyethylene bearing is inserted into each protrusion recess of the acetabular cup, and each insertion protruding portion of the polyethylene bearing is inserted into each insertion recess of the acetabular cup. an acetabular cup comprising a seating recess, a female taper formed on an inner wall, a plurality of protrusion recesses formed to communicate with the seating recess and disposed along the circumferential direction of the acetabular cup, and a plurality of insertion recesses formed inside the plurality of the protrusion recesses; and a bearing (200; 300) comprising a polyethylene bearing made of polyethylene material, the polyethylene bearing comprising an outer circumference having a male taper, a plurality of protrusions disposed along the circumferential direction of the polyethylene bearing and protruding in the radial direction, and a plurality of insertion protruding portions each formed on the outer portion of each of the protrusions and protruding on the outer portion of each of the protrusions,, and comprising a ceramic bearing made of a ceramic material, which ceramic bearing comprises a male taper formed on the lower portion of the ceramic bearing 300, wherein when the polyethylene bearing is engaged with the acetabular cup, the male taper of the polyethylene bearing is engaged with the female taper of the acetabular cup, and when the ceramic bearing is with the acetabular cup, the male taper of the ceramic bearing is engaged with the female taper of the acetabular cup, characterised in that the acetabular cup assembly is adapted such that when the polyethylene berning is engaged with the acetablular cup, each protrusion of the polyethylene bearing is inserted into each protrusion recess of the acetabular cup, and each insertion protruding portion of the polyethylene bearing is inserted into each insertion recess of the acetabular cup.