An air conditioner indoor unit, comprising: a housing, the housing including a first accommodating portion having a first accommodating space and a second accommodating portion having a second accommodating space, the first accommodating portion having an air outlet, and the second accommodating space being located at a front side of the first accommodating space; an inner air deflector, the inner air deflector being pivotally disposed in the first accommodating space; an outer air deflector, the outer air deflector being pivotally disposed in the second accommodating space; and two outer driving devices, the two outer driving devices being respectively disposed at a left side and a right side of the housing to drive the outer air deflector to rotate between a second closed position and a second open position; wherein the housing includes: an outer cover, wherein the first accommodating portion is disposed on the outer cover; and a left side cover and a right side cover respectively disposed at a left side and a right side of the outer cover, the second accommodating portion being jointly constituted by the outer cover, the left side cover and the right side cover; characterized in that, when the inner air deflector is in a closed state, a thickness of an upper end of the inner air deflector is larger than a thickness of a lower end of the inner air deflector; the first accommodating portion includes a first arc panel protruding backward, and a first left side plate and a first right side plate that are respectively located at a left side and a right side of the first arc panel; the first arc panel, the first left side plate and the first right side plate define the first accommodating space, and the inner air deflector is pivotally mounted in the first accommodating space. a housing, the housing including a first accommodating portion having a first accommodating space and a second accommodating portion having a second accommodating space, the first accommodating portion having an air outlet, and the second accommodating space being located at a front side of the first accommodating space; an inner air deflector, the inner air deflector being pivotally disposed in the first accommodating space; an outer air deflector, the outer air deflector being pivotally disposed in the second accommodating space; and two outer driving devices, the two outer driving devices being respectively disposed at a left side and a right side of the housing to drive the outer air deflector to rotate between a second closed position and a second open position; wherein the housing includes: an outer cover, wherein the first accommodating portion is disposed on the outer cover; and a left side cover and a right side cover respectively disposed at a left side and a right side of the outer cover, the second accommodating portion being jointly constituted by the outer cover, the left side cover and the right side cover; an outer cover, wherein the first accommodating portion is disposed on the outer cover; and a left side cover and a right side cover respectively disposed at a left side and a right side of the outer cover, the second accommodating portion being jointly constituted by the outer cover, the left side cover and the right side cover; characterized in that, when the inner air deflector is in a closed state, a thickness of an upper end of the inner air deflector is larger than a thickness of a lower end of the inner air deflector; the first accommodating portion includes a first arc panel protruding backward, and a first left side plate and a first right side plate that are respectively located at a left side and a right side of the first arc panel; the first arc panel, the first left side plate and the first right side plate define the first accommodating space, and the inner air deflector is pivotally mounted in the first accommodating space.