PURPOSE: To enable fine solid particles to be taken out efficiently from exhaust gases by dusting the captured material having stuck on a bag filter provided with a slow speed automatic rotating mechanism at the rear end of a purifying cylinder by means of brushes and compressing the dusted material.

CONSTITUTION: An exhaust gas of engines etc. is admitted via a lead-in pipe 3 into a purifying cylinder 1, is passed through an expansion chamber 5, a squeeze plate 7, a condensing chamber 6 and a capturing chamber 9 inserted internally with heat- resistance capturing materials 10 so that it undergoes the processes of coupling and growing the fine particles in the gas over two stages. This gas is then flowed into a bag filter 13. The vibrations with engine operations and vehicle traveling are absorbed by a brush part 15b and a sleeve 14 and a filter 13 are successively and automatically rotated at a slow speed by the end thereof. The captured material having stuck on the filter 13 is dusted by brushed 15, 19, falls into the cylinder, is compressed by a piston 22 and is discharged intermittently from a pressing cover 24.