To prevent a labor of redetection by employing stored inserted grain data even if a power supply for an ccperation handling apparatus is again turned on when the power supply for the operation handling apparatus is turned off in the state where grains are inserted into a storage chamber.

A detection processing where detection is performed with each throwing amount sensor is started (step 101), and when a power supply for an operation apparatus is on (step 102), a thrown grain amount is detected by each throwing sensor (step 103), a detected thrown grain amount is inputted into a controller (step 104), and the detected thrown grain amount is stored and held (step 106). When the power supply of the operation apparatus is turned off (step 107), and the power supply is again turned on (step 108), the thrown grain amount is not detected anew (step 109), the detected thrown grain data when the power supply is off stored in a nonvolatile memory is used (step 110), and a full amount of the thrown grain amount is detected (step 111).