Dryer and controlling method thereof

A dryer is disclosed. The dryer includes a heat exchanger configured to remove moisture from air flowing and heat and discharge the moisture-removed air, a drum containing a material to be dried, a humidity sensor configured to detect a humidity of the air flowing from the drum, a fan configured to generate a flow of the air flowing along a flow path formed so that the air discharged from the heat exchanger flows to the heat exchanger via the drum and the humidity sensor, and a processor configured to determine a dried state of the material to be dried based on the humidity detected through the humidity sensor, and the humidity sensor is disposed at a position where a flow velocity of the air is equal to or higher than a predetermined velocity in the flow path formed between the drum and the heat exchanger.