Abstract: A dust box includes: an attachment portion configured to be attached to a dust-discharging nozzle extending from a housing of an electric tool; and a dust-collecting portion connected to the attachment portion and configured to store dust particles to be discharged from the nozzle. The dust-collecting portion mainly consists of a box which is made of synthetic resin and configured to be detachably connected to the attachment portion, and a paper bag received in the box and configured to store the dust particles to be discharged from the nozzle.