A microaspiration-based lung window apparatus for use with a confocal optical microscope for obtaining a microscopic image of a lung tissue, the apparatus comprising: an open window configured to open in upper and lower parts thereof, have a cover glass placed on the upper part thereof, and have a lung tissue brought in contact with the lower part thereof; a suction tube configured to extend to a suction device from a side of the open window and make the inside of the open window vacuum; characterized in that the apparatus further comprises: a tilting mount seat , configured to extend from a side of the open window , in which a tilting mount is placed to adjust the angle of the lung window apparatus, so that in case that a confocal microscope system and its objective lens are connected to the microaspiration-based lung window apparatus the cover glass and an objective lens of a confocal microscope system are maintained in parallel, wherein the open window and the suction tube are formed in a first plate which has a first body and first protrusions having a step with respect to the first body and protruding from sides of the first body , and the tilting mount seat is formed in a second plate which has a second body and second protrusions having a step with respect to the second body and joining with the first protrusions . an open window configured to open in upper and lower parts thereof, have a cover glass placed on the upper part thereof, and have a lung tissue brought in contact with the lower part thereof; a suction tube configured to extend to a suction device from a side of the open window and make the inside of the open window vacuum; characterized in that the apparatus further comprises: a tilting mount seat , configured to extend from a side of the open window , in which a tilting mount is placed to adjust the angle of the lung window apparatus, so that in case that a confocal microscope system and its objective lens are connected to the microaspiration-based lung window apparatus the cover glass and an objective lens of a confocal microscope system are maintained in parallel, wherein the open window and the suction tube are formed in a first plate which has a first body and first protrusions having a step with respect to the first body and protruding from sides of the first body , and the tilting mount seat is formed in a second plate which has a second body and second protrusions having a step with respect to the second body and joining with the first protrusions . a tilting mount seat , configured to extend from a side of the open window , in which a tilting mount is placed to adjust the angle of the lung window apparatus, so that in case that a confocal microscope system and its objective lens are connected to the microaspiration-based lung window apparatus the cover glass and an objective lens of a confocal microscope system are maintained in parallel, wherein the open window and the suction tube are formed in a first plate which has a first body and first protrusions having a step with respect to the first body and protruding from sides of the first body , and the tilting mount seat is formed in a second plate which has a second body and second protrusions having a step with respect to the second body and joining with the first protrusions . <EOS>