Provided are a solid culture raw material fill-in control mechanism and a solid culture raw material fill-in control method that can automatically prevent the occurrence of a difference in the number of deposited layers in the circumferential direction of the raw material at the end of filling-in and can also be applied to existing facilities. A predicted time from the detection of the raw material exhaustion by the raw material detection means 81 a to the completion of the filling is set to a value previously determined before the start of the operation or a value determined from the raw material processing speed based on the detection of the movement of the raw material during the operation, Calculates the number of remaining rounds until the completion of the filling from the set value of the number of rounds from the start of the filling to the completion of the filling...