To provide an energy-saving and highly economical dust collector which is superior in a sweeping off performance of dust collected in a filter cloth without being affected by the filter cloth being extended and shortened, and capable of setting the length of the filter cloth long and operating continuously.

This filtration type dust collector 100 collects dust at the inside of a filter cloth 20 by allowing a gas containing dust to flow downward from the upper part and allowing the gas to pass through the cylindrical filter cloth 20 from inside towards outside. The filter cloth 20 has openings at both ends in the length direction. The upper and the lower ends of the filter cloth 20 are respectively mounted on an upper mounting plate 30 and a lower mounting plate 31 which are installed in a housing 10 and respectively provided with through holes 32 and 33, and further, the lower end is provided with means 24, 25, 26 to cope with the extension or shrinkage in the lengthwise direction of and equalize the tension of the filter cloth 20. A pulse jet air generator 40 provided in the upper part injects the upper part of the filter cloth 20 with pulse jet air to let the dust collected by the filter cloth 20 being swept off.