Dust collector and electric vacuum cleaner

The invention provides a dust collector (6) capable of suppressing the backflow of dust accumulated in a first dust collecting part (12), and an electric vacuum cleaner equipped with the dust collector (6). The dust collector (6) includes a first separating part (11) for centrifugally separating dust; and a first dust collecting part (12) for collecting the dust separated by the first separating part (11). The dust collector (6) has a cylindrical cup portion (20), a cylindrical enlargement portion (33), a ventilation portion (35), and a backflow prevention portion (37). Dust-containing air isintroduced into the cup portion (20). The enlargement portion (33) is disposed inside the cup portion (20) and is disposed at a position between the enlargement portion (33) and the first dust collecting part (12). The ventilation portion (35) is formed on a side of the enlargement portion (33) close to the first separating part (11) and can be ventilated from the side of the first dust collectingpart (12) toward the side