To provide an opening holding instrument having the simplest shape and a wide range of application, and capable of safely and reliably filling all sorts of powdered and granular articles into all kinds of bag-shaped containers by a manual operation in the most efficient manner for a number of workers and time.

The opening holding instrument is formed of a single material of a synthetic resin and has a simple structure of a tapered cylinder with a vertical cut and open portion through its body. By utilizing the free expansion and contraction of the cylinder due to its elasticity, the holding instrument is pressed against a bag to make its opening self-supported, thereby making the filling of powdered and granular materials into the bag easier.