To provide a low cost and simple dust-removing device using a highly durable resin net durable for a long period of use, so as to remove the dust which can not be completely removed through a steel screen provided in water-intake (drainage) facilities in a hydraulic power generation water introduction channel or an agriculture drainage channel.

The fixing wire (A) constituting a simple dust-removing installation X is set to the fixing hook (G) of a water channel upper end and a lower stage flat bar (C) is hang down to the lower stage of an existing steel screen, so as to complete the setting. When the highly durable resin net (B) of the simple dust-removing device catches the dust flowing down in the water channel, the hoisting wire (F) arranged at the center of the lower stage flat bar (C) is manually hoisted through a via-eye bolt (E) at the center of the upper end flat bar (D). When the upper end flat bar (D) is overlapped with the lower stage flat bar (C), while shifting from the hoisting wire (F) to the upper and lower stage flat bars (C, D), the resin net is taken out of the water channel for removal of the dust.