A wet process image forming apparatus using a developing liquid consisting of a carrier liquid and a toner dispersed therein, in which air containing carrier vapor produced in, e.g., a fixing section, is sucked by a suction fan via a first duct into a liquefying section. The liquefying section liquefies the carrier vapor and water vapor. A separating section is disposed below the liquefying portion and includes a receptacle. A liquid produced by the liquefying section is caused to flow down into the receptacle along a chain due to its own weight. The separating section separates the liquid into the carrier liquid and water on the basis of a difference in specific gravity. Only the carrier overlying the water in the receptacle is fed to a carrier tank via overflow ports formed in the wall of the receptacle. The water is delivered to a water tank via a pipe. The pipe is so configured as to maintain the liquid level in the receptacle substantially at the level of the overflow ports.