To recover a transport pipe which is about to clog from clogging by deforming and vibrating an internal pipe member by making compressed air flow in an air gap provided between the inner peripheral surface of an external pipe part and the internal pipe member when a line transportation is performed for particulate matter in the hollow part of the internal pipe member.

When powder and grain B within a hopper A is sucked by negative pressure within a line C and particulate matter B is transported within the line C, compressed air is supplied from an air supply port 4 to an air gap 3 of a double pipe constituted of an internal pipe member l deforming and vibrating due to air flow and an external pipe part 2 with rigidity which does not deform and vibrate due to air flow, air is discharged from a discharge port 5 and the internal pipe member 1 is vibrated by vibration of air flow. As for the diameter of the internal pipe member 1 for the external pipe part 2, no matter is fixed in particular but it is desirable that the inner diameter of the internal pipe member 1 is reduced to about 1% to 20% of the inner diameter of the external pipe part 2. Thus, a transport pipe which is going to clog is recovered from clogging and clogging of particulate matter whose particulate diameter is very small can be evaded.