To provide a fixing implement capable of not only simply and securely fixing between two face plates but also applying for other concrete forms by a simple constitution.

A fixing implement 10 is constituted of a first L-shaped rail 11 where both upper and lower ends of a pushing part 11a come into contact with the upper and lower angle parts 21a formed at both upper and lower ends of the first face plate 21, a second L-shaped rail 12 that the pressing part 12a abutting on the outside face of a second face plate 22, a fixing lever 14 rotatably pivoted by a pivoting shaft 13 fitted to one side of both L-shaped rails 11, 12, and an oblong hole 12c formed in the other one of the both L-shaped rails 11, 12 to make the pivoting shaft 13 movable, and a first pushing part 14a and a second pushing part 14b abutting on the inside face of the other L-shaped rail 12 and pushing out of the one side L-shaped rail 11 are formed at both sides of the pivoting shaft 13 of the fixing lever 14.