To provide an odorless apparatus for generating formalin gas, capable of widely filling the gas and carrying out sterilization.

This odorless apparatus for generating the formalin gas has a bottle body 1 storing a formalin liquid in the interior, and having an opening part exposed in an open-lid state and sealed with a sealing member 3, a heater 4 for carrying and heating the bottle body 1, a nozzle device 30 having a bubbling nozzle 5 and a vaporizing nozzle 6 each having a tip with a pointed shape, and constituted so as to be moved upward and downward to the bottle body 1 on the heater 4, a lifting device 10 for driving the nozzle device 30 upward and downward, an air-feeding part 40 for feeding clean air to the bubbling nozzle 5 to bubble the interior of the bottle body 1, an ejector 18 for mixing the formalin discharged from the vaporizing nozzle 6, with the air, a discharging air-feeding part 41 for feeding the clean air to the ejector 18, and a cleaning treating part arranged at the upper part of the bottle body 1 on the heater 4, and for making the formalin gas rising to the upper part of the bottle body 1 odorless and clean.