To provide a grain dryer uniformizing a moisture value without causing unevenness in moisture due to difference in grain moisture before and after passing through a drying portion at the termination of drying, even when an adjustment moisture value by additional drying as additional drying processing for finely adjusting the moisture after the termination of drying, is small.
This grain dryer is provided with an operation control portion 19 for drying the grain charged into a storage chamber 2 to a target set moisture value by a drying cycle operation to supply drying hot air to a drying portion 3 while circulating the grain. The operation control portion 19, after achieving configuration that enables the drying cycle operation according to the drying speed set by the temperature control of the drying hot air of the drying portion 3, performs drying processing at a drying speed determined on the basis of an additional drying time and the adjustment moisture value, on the additional drying time determined to be the integral multiple of one-cycle time of the circulated grain, by setting the adjustment moisture value for additional drying after the drying processing by the drying cycle operation to the target set moisture value.
Maki Reiko
Kimio Kikutani