An automatic purification apparatus for isolating target nucleic acids from a plurality of biological samples, comprising: a purification block 110 moving vertically and horizontally, wherein a plurality of pipettes P or a plurality of magnet rod tubes are installed in the purification block 110; a solution drip tray 1050 disposed apart from lower ends of the plurality of pipettes P or the plurality of magnet rod tubes, wherein the solution drip tray 1050 is movable between a first position where the solution drip tray 1050 can receive solution drips from the plurality of pipettes P or the plurality of magnet rod tubes and a second position where the solution drip tray 1050 can avoid in contact with plurality of pipettes P or the plurality of magnet rod tubes when the purification block 110 is moved down; and an aerosol prevention part 1070 disposed on outer surface of the purification block 110 vertically movably along the outer surface of the purification block, wherein the aerosol prevention part 1070 moved downward so that end portion of the aerosol prevention part 1070 is be tightly contacted with the solution drip tray 1050 to cover smeared portions of the plurality of pipettes P or the plurality of magnet rod tubes when the solution drip tray 1050 is moved to the first position, wherein the smeared portions of the plurality of pipettes P or the plurality of magnet rod tubes are shut off when the purification block is moved in a horizontal direction so that, the generation of aerosol and the cross pollution are prevented since a vortex of air is not generated when the purification block having the plurality of pipettes or the plurality of magnet rod tubes is moved horizontally. a purification block 110 moving vertically and horizontally, wherein a plurality of pipettes P or a plurality of magnet rod tubes are installed in the purification block 110; a solution drip tray 1050 disposed apart from lower ends of the plurality of pipettes P or the plurality of magnet rod tubes, wherein the solution drip tray 1050 is movable between a first position where the solution drip tray 1050 can receive solution drips from the plurality of pipettes P or the plurality of magnet rod tubes and a second position where the solution drip tray 1050 can avoid in contact with plurality of pipettes P or the plurality of magnet rod tubes when the purification block 110 is moved down; and an aerosol prevention part 1070 disposed on outer surface of the purification block 110 vertically movably along the outer surface of the purification block, wherein the aerosol prevention part 1070 moved downward so that end portion of the aerosol prevention part 1070 is be tightly contacted with the solution drip tray 1050 to cover smeared portions of the plurality of pipettes P or the plurality of magnet rod tubes when the solution drip tray 1050 is moved to the first position, wherein the smeared portions of the plurality of pipettes P or the plurality of magnet rod tubes are shut off when the purification block is moved in a horizontal direction so that, the generation of aerosol and the cross pollution are prevented since a vortex of air is not generated when the purification block having the plurality of pipettes or the plurality of magnet rod tubes is moved horizontally.