To prevent dispersion of the dust collection amount to be collected, and inversive ionization thereof.

An electric dust collector (1) includes a plurality of sets of dust collection mechanisms (11 to 13) which are juxtaposed along the gas flow direction and collect dust by imparting charges to the dust contained in gas, and a charging rate adjusting unit (23) for adjusting the charging rate in the dust collection mechanisms (11 to 13). The charging rate adjusting unit (23) adjusts the charging rate of at least the dust collection mechanism (11) installed on the most-upstream side of the gas flow direction out of the plurality of sets of dust collection mechanisms (11 to 13) to the charging rate different from that of other dust collection mechanisms (12, 13), in particular, the charging rate lower than that of other dust collection mechanisms (12, 13).