A plurality of recording head units are supported by a holder in an integrated manner. The recording head units and pairs of rollers which hold a sheet are arranged alternately along a sheet conveying direction. An elastic member is disposed in a clearance between the holder and each of the recording head units supported by the holder in an elastically deformed manner to form an airtight seal. The airtight seal prevents upward leakage, from the clearance, of the humidifying gas introduced into the narrow space to which ink nozzles of the recording head units are exposed.