A mask device for covering a user's nose and mouth, the mask device comprising: a mask body including a front cover to form an outer appearance of the mask body, a rear cover coupled to and facing the front cover; the rear cover which can be located in front of the user's nose and mouth when the mask device is worn by the user; the rear cover having a substantially similar shape as the front cover and placed behind the front cover, whereby the top and bottom edges of the front and rear covers (11, 12) are connected to define a space between the front and rear covers (11, 12); the rear cover including at least one inlet (111a, 111b) and at least one outlet (112a, 112b) located below the inlet (111a, 111b); and the rear cover defining a breathing space for receiving filtered air between the rear cover and the user's nose and mouth, and a partition plate disposed between the rear cover and the front cover, the partition plate forming an upper space and a lower space in the mask body, and a first air cleaner and a second air cleaner to filter outside air sucked in from an outside environment and to supply the filtered air to the mask body, the first air cleaner coupled to one side of the mask body and the second air cleaner coupled to another side of the mask body, wherein the at least one inlet (111a, 111b) are openings for supplying air filtered from the first air cleaner and the second air cleaner in the direction toward the user's nose and mouth, and the at least one outlet (112a, 112b) are openings for discharging air discharged from the user's nose and mouth to the outside environment, wherein the upper space of the mask body is in communication with the first air cleaner, the second air cleaner, and the at least one inlet (111a, 111b), and the lower space of the mask body is in communication with the at least one outlet (112a, 112b), and wherein the mask body comprises a first fixing part on one side of the mask body and a second fixing part on the other side of the mask body, and the first air cleaner and the second air cleaner are detachably mounted to the first fixing part and the second fixing part, respectively. a mask body including a front cover to form an outer appearance of the mask body, a rear cover coupled to and facing the front cover; the rear cover which can be located in front of the user's nose and mouth when the mask device is worn by the user; the rear cover having a substantially similar shape as the front cover and placed behind the front cover, whereby the top and bottom edges of the front and rear covers (11, 12) are connected to define a space between the front and rear covers (11, 12); the rear cover including at least one inlet (111a, 111b) and at least one outlet (112a, 112b) located below the inlet (111a, 111b); and the rear cover defining a breathing space for receiving filtered air between the rear cover and the user's nose and mouth, and a partition plate disposed between the rear cover and the front cover, the partition plate forming an upper space and a lower space in the mask body, and a first air cleaner and a second air cleaner to filter outside air sucked in from an outside environment and to supply the filtered air to the mask body, the first air cleaner coupled to one side of the mask body and the second air cleaner coupled to another side of the mask body, wherein the at least one inlet (111a, 111b) are openings for supplying air filtered from the first air cleaner and the second air cleaner in the direction toward the user's nose and mouth, and the at least one outlet (112a, 112b) are openings for discharging air discharged from the user's nose and mouth to the outside environment, wherein the upper space of the mask body is in communication with the first air cleaner, the second air cleaner, and the at least one inlet (111a, 111b), and the lower space of the mask body is in communication with the at least one outlet (112a, 112b), and wherein the mask body comprises a first fixing part on one side of the mask body and a second fixing part on the other side of the mask body, and the first air cleaner and the second air cleaner are detachably mounted to the first fixing part and the second fixing part, respectively.