The invention discloses an anti-bird nest device, which relates to the technical field of electric power facilities. The anti-bird's nest device comprises a tightening mechanism and an operating lever. The tightening mechanism comprises an upper top cover and a lower pulling cover. A central post and spring steel sheets are disposed between the upper top cover and the lower pulling cover. A plurality of spring steel sheets are provided and are disposed around the central post at intervals. The upper end of the central post is fixed at the middle part of the upper top cover, and the lower end of the central post traverses through the middle part via hole of the lower pulling cover. A clamping slot cooperating with the operating lever is disposed at the excircle of the lower end of the central post. A tension spring is disposed between the central post and the spring steel sheet, under the lower pulling cover. A stay rope at the lower end of the tension spring traverses through the via hole of the lower pulling cover and is connected to a driving mechanism of the lower end of the central post. The tension spring can spring back through the driving mechanism, and the lower pulling cover can be driven upwardly, and the spring steel sheets can be bended outwardly and tensioned between a cross arm and an electric pole. The invention is advantageous in that the tension mechanism can be lifted in a gap between the cross arm and the electric pole through the operating lever, and the spring steel sheets can be bended outwardly and tensioned between the cross arm and the electric pole, and therefore the possibility of branch inserting and nest building of birds can be prevented.