To solve the problem of dew formation occurring on surface of a blast tube which sends a cooling gas from a cooling device to a paper conveyance part in the case of cooling a liquid (liquid droplets) and paper when the liquid sticks to the paper.

A cooling means (cooling device) 4 which cools the paper 10 immediately before an image forming part 1 is arranged upstream in a paper conveyance direction of the image forming part 1. The cooling device 4 is equipped with a cooling unit which generates the cooling gas, a heat exchange box including a fan which sends the cooling gas, and the blast tube 44 with a blow-out port (hole) 45 formed to blow the cooling gas towards the paper 10 immediately before the image forming part 1. The blast tube 44 is arranged at a position cooled by the cooling gas blown out from the blow-out port 45 towards the paper 10 and rebounded after brought into contact with the paper.