A machine tool stores a date at which a clogged state of a filter is determined. A control device carries out a tool exchange of a tool exchange device in a long period of time only in a case that elapsed time from the stored date is long. A differential pressure sensor accurately detects a pressure difference between before and after a filter within the long exchange time. A determining unit accurately determines a clogging of the filter based on the accurate pressure difference detected by the differential pressure sensor. The long exchange operation of the tool exchange device is carried out only in a case that a predetermined period of time has passed after the previous clogged state is determined. Production efficiency of the machine tool is hardly reduced
