To provide a dust aggregation pathway which increases a collision frequency of particle each other in a dust with a simple structure so that the particle number can be decreased and also the apparent particle diameter is increased.

The dust aggregation pathway has an extension pipe 502, a suction hose 504 and a connection part 505, as a passage where a gas containing the dust flows, an attrition charge pathway 161 for attrition charging the dust, arranged in the extension pipe 502, and a collision promotion pathway 162, arranged in the connection part 505, for promoting a formation of a dust lump (a cluster) by making a charged dust collide each other in the attrition charge pathway 161, wherein the attrition charge part 161 has a first attrition discharge part formed of a first material and a second attrition charge part formed with a second material, and the attrition promotion pathway 162 is formed of a third material, wherein the contact potential of the first material is larger than the contact potential of the third material, and the contact potential of the third material is larger than the contact potential of the second material.