PURPOSE: To efficiently perform drying of grains by a method wherein degree of drying is measured at predetermined intervals and whether or not desired finishing moisture value has been obtained is judged based on the differences in the degree of drying between before and after the lapse of a predetermined time intervals so that drying is stopped or continued depending on the result of the judgement.

CONSTITUTION: Detection signals of a grain moisture meter incorporated into a cargo metering equipment and metering signals of a load cell scale incorporated into an assembled hopper 34 are inputted into a control unit 40 of a sample drier 37. And from the control unit, vertical horizontal movement signals of a robot hand 35, charging signals to the hopper 34 or a discharge hopper, open/close signals of discharge shutters 43, and drive signals of a heater 38 and suction fan 39 are outputted. And degree of drying is measured at predetermined intervals and whether or not desired finishing moisture value is obtained is judged based on the differences in the degree of drying between before and after the lapse of a predetermined time period and drying is stopped or continued depending the result of the judgement.