To provide a rapid load testing machine achieved in miniaturization and weight reduction, enhanced in testing work efficiency, having a simple structure and excellent in cost or maintenance properties.

A reaction force receiving device 5 is equipped with a frame part 51 for housing an anchor support member 2 to which an elastomer 4 and a pressure member 3 are attached and the pedestal part 52 formed to the lower end of the frame part and having a pedestal plate 52A which supports the elastomer and has a through-hole 52B, in which the anchor support member can be loosely inserted, formed thereto. A charging hole 51A for charging a large number of steel spheres 8, 8, etc. is formed to the frame part at the position opposed to the pressure member in a state that the elastomer is compressed and a large number of the steel spheres 8, 8, etc. become a temporary stop state that the compressed state is kept by locking the pressure member and a large number of the steel spheres 8, 8, etc. are detached to release the temporary stop state.