To provide a dust collector with high dust collecting efficiency.

This dust collector is equipped with a box body, a motor set inside the box body, and a rotary brush 2 driven by the motor. On the bottom face 13 in the box body, a dust suction port 3 to face the floor face is opened. Inside the box body, a rotary brush-housing chamber to house the rotary brush 2 is formed, the rotary brush 2 is constituted of a rotation shaft with pivotally supported both ends and a brush part 21 formed on the periphery face of the rotation shaft. The rotary brush housing chamber is equipped with a brush part-housing area and two shaft support areas 19 equipped on both sides of the brush part-housing area. The tip end of the brush part 21 of the rotary brush 2 faces the dust suction port 3. A lid member 15 to suppress the air stream flowing from a gap between the floor face and the bottom face 13 of the box body into the brush housing area via the shaft support area 19 in the rotary brush housing chamber is placed in the flow passage of the air stream flowing from the gap between the floor face and the bottom face 13 of the box body into the shaft support area 19 and covers the shaft support area 19.