Screw machine with a rotatable filter in a deaeration port

A screw machine comprising:

• a screw configured to be rotationally driven about an axis by a driving source;
• a barrel having a screw hole into which the screw is inserted and a de-airing port configured to discharge air inside the screw hole;
• a filter configured such that a part thereof faces the de-airing port of the barrel;
• a filter driving unit configured to move the filter to shift the part of the filter facing the de-airing port;
• a vacuum pump configured to suck the air inside the screw hole from the de-airing port through the filter;
• and
• a filter housing having an accommodating space and attached to the barrel, the filter being accommodated in the accommodating space, wherein
• the vacuum pump is configured to suck the air inside the screw hole through a suction port, the suction port being formed in the filter housing so as to open to the accommodating space,
• the filter driving unit is configured to rotate the filter, and
• as the filter is rotated by the filter driving unit, a part of an outer circumferential surface of the filter facing the de-airing port is moved and comes to face the de-airing port again in the accommodating space.