Provided is a respiratory filter device having a filter module, a connection curved holder, an adjustable curved holder, and a mask. The filter module has a housing body, and both the connection curved holder and the adjustable curved holder have a respective free end and a respective connection end opposite to each other. The connection ends of the connection curved holder and the adjustable curved holder are connected with the filter module, and the free ends face to each other and form an opening between the free ends. The filter module is connected to the connection curved holder and the adjustable curved holder to define an accommodation space adjacent to the opening. Accordingly, the respiratory filter device can be worn on a users head or neck directly by the accommodation space, for allowing the user to do other work when wearing the respiratory filter device.
