To improve convenience for use and generality by operating a pin member with substantially equal pressing force even when the same clips are different in board thickness, lightening the engagement holding force and clamping force of leg parts when the board thickness is large, and increasing the same when it is small.

This clip 1 includes: a grommet 3 having an elastic leg part 30 with an insert hole 30a and a flange part 35; and a pin member 2 having a head part 20 and a shaft part 22, wherein the leg part 30 is inserted in mounting holes M1, P1 of the respective plate members M, P, and the shaft part 22 is pressed in the insert hole 30a by the pressing operation of the pin member 2 to expand the leg part 30, thereby holding the plate members M, P between the expanded corresponding parts of the flange part 35 and the leg part 30. In the flange part 35, a projecting part 39b is projected on the peripheral part side at a predetermined distance from the base end 36 side connected to the leg part 30, and the part between the base end 36 and the projecting part 39b is formed as a deformed part 38 elastically displaceable up and down.