Ceiling air conditioner

A ceiling air conditioner comprising:

• a cross-flow fan extending in a first direction;
• a case defining an internal space in which the cross-flow fan is mounted;
• a front panel coupled to the case and having a suction part through which indoor air is suctioned and a discharge part through which air is discharged toward a room;
• a heat exchanger configured to exchange heat with air suctioned into the case and to partition the internal space into a suction flow path and a discharge flow path;
• a rear guide installed between the discharge part and the heat exchanger and configured to guide air which has passed through the heat exchanger to the discharge part;
• and
• protrusions including at least one protrusion surface and disposed at both side surfaces or one side surface defining the discharge part or the discharge flow path, the protrusions being configured to change a length of the discharge flow path in the first direction based on an air discharge direction.