The widespread ideas in properties of the toroidal dust obscuration (torus) of active
galactic nuclei (AGN) successfully explained the two types of AGN that type 1 and 2 AGN
are intrinsically the same, but they are viewed with face-on and edge-on from the
observers. However, the dust structures of the tori are not well understood due to their
small scale (r<10 pc). One of the crucial way to proceed torus studies are mid-infrared
(3-20 um) observations which trace well the torus dust emission.

Based on the data obtained by Subaru/COMICS, Gemini/T-ReCS, AKARI/IRC, and WISE, I will
present our recent torus studies including 1) the torus media (smooth vs. clumpy) 2)
expected torus size based on the torus model 3) the connection between the tori and
their host galaxies, and 4) the AGN torus candidates with extreme obscuration end
(buried and dust poor AGN).