To provide a measuring device for a powder and granular material capable of accurately measuring the powder and granular material with a simple structure at a low cost.

In a measuring error calculating step (S2), a measuring error is calculated as follows: at a measuring error calculating forward step (S13), the measuring error is calculated from a difference between a measuring actual value (Wc(n)) measured this time and a sampling measuring integration logical value (n×ΔW); and at a measuring error calculating-back step (S12), the measuring error is calculated from a difference between a remaining necessary measuring logical value (Wi-n×ΔW) which is calculated from a difference between a standard measuring logical value (Wi) and the sampling measuring integration logical value (n×ΔW), and a remaining necessary measuring actual value (Wi-Wc(n)) which is calculated from a difference between the standard measuring logical value (Wi) and the measuring actual value (WC(n)) measured this time. The measuring error is calculated by the measuring error back calculating step in the first half of the measuring operation and is calculated by the measuring error sequential calculating step in the latter half of the measuring operation.