To provide a void form fixing implement which is excellent in workability because a void form can be easily fixed by assembly on a construction site, which is excellent in conveyability by virtue of a reduction in weight and bulk, and which is excellent in constructibility because even a person except a skilled worker can perform assembling work.

This void form fixing implement 1 is equipped with: a long bottom fixing body 2 which is to be placed on a lower reinforcing bar; a plurality of locking parts 4 which are formed at predetermined intervals in the longitudinal direction of the fixing body 2; and an upper-part fixing body 5 for fixing the void form 10, which is formed of a strip-shaped body or a linear body, whose prescribed part is locked by the locking part 4, and which is placed in a direction orthogonal to the longitudinal direction of the fixing body 2.