To provide a vaporization filter capable of keeping high humidifying performance for a long period by suppressing attachment of scale.

A layered aggregate of a single-faced corrugated board made of a water-absorbing filter element including an antibacterial agent and an antifungal agent, holds a water retention agent on pored cross-section at a windward side of the layered aggregate. Moisture quickly evaporates at a windward side of the vaporization filter, which is origination of attachment of scale, and causes aged deterioration of the humidifying performance. As the water retention agent is held on the pored cross-section at the windward side, the vaporization filter can be prevented from drying, and the attachment of scale can be prevented. The water retention agent is layered silicate mineral or polyalkylene oxide water-absorbing resin.