To provide an inkjet printer capable of stably supplying ink to a recording head by preventing, for a long term, evaporation of water due to pressurizing the ink or increasing of the viscosity of the ink caused by the water evaporation in the inkjet printer, particularly a line type inkjet printer.

This inkjet printer 1 comprises a recording head 3 having a nozzle 5 mounted thereon for ejecting ink 4 to a recording medium P, an intermediate tank 9 for applying back-pressure to the nozzle 5 of the recording head 3, and pressuring/moisturizing means 14, 15, 20 for pressurizing the inner section of the intermediate tank 9 by injecting a moisturized air thereto.