PURPOSE: To maintain selection state of treated material well by operating an actuator so that a set selection state corresponding to a state of small amount of treated material is obtained when a treated material detecting sensor does not continuously discover the treated material for ≥set time.

CONSTITUTION: Operation of an actuator to regulate a selection device B is stopped as a treated material detecting sensor S1 to discover whether the treated material is fed to a squeezing chamber A or not does not detect supply of the treated material. The actuator is worked in such a way that a set selection state corresponding to a state of small amount of treated material is obtained when the sensor S1 does not continuously discover the treated material for ≥set time.