PURPOSE: To achieve an accurate quantitative sampling with an improved reproducibility and a simple structure by providing a cut recessed part for a sampling part on a tip outer-periphery surface and a dust seal, an elimination plate, etc.

CONSTITUTION: When fallen particles within a process line P is deposited in a heap within a cut recessed part 12a and a shaft 12 retreats, the particles in a heap of the upper side of the shaft 12 and the recessed part 12a are rubbed off. Further, the recessed part 12a is also rubbed off when passing dust seals 14 and 15 to be level with the outer-periphery surface of the shaft 12. The shaft 12 stops when a rear-edge part reaches a stopper 22, a shutter opens and a hopper 18 is released, the shutter 12 and the recessed part 12a rotate, and the inside particle is released into the hopper 18. Residual particles are completely scratched off by enabling a third air cylinder 25 to start driving and a scratching rod 24 to move up and down inside the recessed part 12a.