A plastic clip, comprising: a clip boss integrally formed with a fixed panel; and a clip main body detachably assembled to the clip boss, wherein the clip boss includes: fitting portions provided in two lower side portions of a vertical plate having a fitting hole; and locking projections provided in front and back upper ends of the fitting portions; and wherein the clip main body includes: an input portion having an inverted triangular shape and provided in a lower end portion; and locking projections provided in upper end portions of the input portion; wherein, the plastic clip further comprises: a clip-boss input guide hole provided in a center of an upper end; clip-boss input guide portions provided in a center of an internal upper portion and connected to the clip-boss input guide hole; and an elastic fitting piece provided in a lower end portion of a first one of the clip-boss input guide portions, wherein the elastic fitting piece has one side portion as a fixed end integrally formed in the lower end portion of the first clip-boss input guide portion on one side; wherein clip-boss support projecting portions are provided on two internal sides of the input portion; and a connecting piece is provided between the lower end portion of the first clip-boss input guide portion and the clip-boss support projecting portion on the one side, wherein the elastic fitting piece is integrally formed with the connecting piece; characterized in that the elastic fitting piece has as another side portion a free end sealing a lower portion of a second one of the clip-boss input guide portions on the other side, and a locking projection in a lower end on a free end side. a clip boss integrally formed with a fixed panel; and a clip main body detachably assembled to the clip boss, wherein the clip boss includes: fitting portions provided in two lower side portions of a vertical plate having a fitting hole; and locking projections provided in front and back upper ends of the fitting portions; and fitting portions provided in two lower side portions of a vertical plate having a fitting hole; and locking projections provided in front and back upper ends of the fitting portions; and wherein the clip main body includes: an input portion having an inverted triangular shape and provided in a lower end portion; and locking projections provided in upper end portions of the input portion; an input portion having an inverted triangular shape and provided in a lower end portion; and locking projections provided in upper end portions of the input portion; wherein, the plastic clip further comprises: a clip-boss input guide hole provided in a center of an upper end; clip-boss input guide portions provided in a center of an internal upper portion and connected to the clip-boss input guide hole; and a clip-boss input guide hole provided in a center of an upper end; clip-boss input guide portions provided in a center of an internal upper portion and connected to the clip-boss input guide hole; and an elastic fitting piece provided in a lower end portion of a first one of the clip-boss input guide portions, wherein the elastic fitting piece has one side portion as a fixed end integrally formed in the lower end portion of the first clip-boss input guide portion on one side; wherein clip-boss support projecting portions are provided on two internal sides of the input portion; and a connecting piece is provided between the lower end portion of the first clip-boss input guide portion and the clip-boss support projecting portion on the one side, wherein the elastic fitting piece is integrally formed with the connecting piece; characterized in that the elastic fitting piece has as another side portion a free end sealing a lower portion of a second one of the clip-boss input guide portions on the other side, and a locking projection in a lower end on a free end side.