Provided is a floating type humidifier, and particularly, a floating type humidifier which can prevent, when a floating type humidifier discharging water particles or vapor while floating on water in a water tank loses a balance thereof and falls, the water stored in the water tank from flushing abruptly and even though a water tank falls due to external force such as an earthquake or carelessness of a user, water stored in the water tank is prevented from being abruptly discharged to minimize a cleaning operation which occurs as much water is discharged, the floating type humidifier can prevent foreign materials from being input in the water stored in the water tank, and the floating type humidifier can be stably used even at places including a hospital, a kindergarten, and a home where a lot of children move.