An automated filament exchange method includes: locating the spool for winding the first filament for the 3D printer; winding the first filament on the subspace of the spool located at the spool location step; allowing the first filament wound at the subspace first filament winding step to pass through a gap formed on the main space flange located between the main space and the subspace; and winding the first filament located at the main space of the spool on the main space of the spool, wherein after the first filament is wound on the subspace of the spool, the first filament passes through the gap and is then wound multi-layeredly on the main space of the spool.

Arranged in the middle of an upper communication sleeve 21 is a first shutter 25 that is moved back and forth in a horizontal open-close direction to open and close a first communication path 23 that makes the inside of a first bobbin chamber 11 and the inside of a furnace body 3 communicate with each other. Arranged in a middle of a lower communication sleeve 53 is a second shutter 57 that is moved back and forth in a horizontal open-close direction to open and close a second communication path 55 that makes a second bobbin chamber 33 and the inside of the furnace body 3 communicate with each other.

Arranged in the middle of an upper communication sleeve 21 is a first shutter 25 that is moved back and forth in a horizontal open-close direction to open and close a first communication path 23 that makes the inside of a first bobbin chamber 11 and the inside of a furnace body 3 communicate with each other. Arranged in a middle of a lower communication sleeve 53 is a second shutter 57 that is moved back and forth in a horizontal open-close direction to open and close a second communication path 55 that makes a second bobbin chamber 33 and the inside of the furnace body 3 communicate with each other.

Arranged in the middle of an upper communication sleeve is a first shutter that is moved back and forth in a horizontal open-close direction to open and close a first communication path that makes the inside of a first bobbin chamber and the inside of a furnace body communicate with each other. Arranged in a middle of a lower communication sleeve is a second shutter that is moved back and forth in a horizontal open-close direction to open and close a second communication path that makes a second bobbin chamber and the inside of the furnace body communicate with each other.

Arranged in the middle of an upper communication sleeve is a first shutter that is moved back and forth in a horizontal open-close direction to open and close a first communication path that makes the inside of a first bobbin chamber and the inside of a furnace body communicate with each other. Arranged in a middle of a lower communication sleeve is a second shutter that is moved back and forth in a horizontal open-close direction to open and close a second communication path that makes a second bobbin chamber and the inside of the furnace body communicate with each other.