carried out throughout the entire region in which the flow of air moves and a function of aromatic substances antibacterial agents and dehumidifying agents is added and the replacement interval for aromatic substances etc is easily and effectively measured fig1 shows the installed filter assembly in the context of one embodiment example of the present invention fig2 shows the overall design of the filter assembly shown in fig1 fig3 shows the installed filter assembly in the context of another embodiment example of the present invention fig4 and fig5 show the installed filter assembly in the context of additional embodiment examples of the present invention fig6 a shows a cross section of the first pleated part and the second pleated part of the filter assembly shown in fig1 fig6 b and fig6 c show a cross section of the first pleated part and the second pleated part of the filter assembly shown in fig3 fig6 d shows a cross section of the first pleated part and the second pleated part of the filter assembly shown in fig4 fig7 a and fig7 b show a cross section of the diffusion member of the filter assembly shown in fig1 fig8 shows the state in which the filter assembly shown in fig1 is installed in the filter channel and fig9 is a diagram showing a filtering system which comprises a filter assembly according to a further embodiment example of the present invention as is clear from fig1 and fig2 the filter assembly 1 according to the present invention consists of a first pleated part 10 a second pleated part 20 an end strip 30 and a diffusion member 40 in the specification of the filter assembly 1 according to the present invention the upper.