Provided is an indoor unit for an air conditioner. The indoor unit for the air conditioner includes a case having at least one suction hole, a heat exchanger disposed at a side of the suction hole, a fan rotatably disposed at a discharge side of the heat exchanger, a front panel coupled to a front portion of the case, the front panel including a discharge part, a discharge panel disposed on the discharge part, and a guide device disposed to surround the fan, the guide device having a curved surface for guiding air discharged from the fan to the guide part.