The invention provides a cylindrical concrete foundation chamfering device which comprises a bottom plate, a positioning assembly and a cutting part. The bottom face of the bottom plate is a plane. The positioning assembly comprises a supporting rod and a rolling wheel. One end of the supporting rod is detachably connected to the bottom plate. The other end of the supporting rod extends out of one side of the bottom plate. The rolling wheel can be rotationally connected to the extending end of the supporting rod and can move towards or away from the bottom plate. The cutting part comprises a connection portion and a cutting portion in a circular arc shape. The connection portion is detachably connected to the bottom plate. The cutting portion and the connection portion are connected and arranged on the same side as the rolling wheel on the bottom plate at intervals. At least one side of the cutting portion is provided with a cutting edge. The cylindrical concrete foundation chamfering device can be assembled according to different chamfering requirements so as to meet the requirements of electric transmission line cylindrical concrete foundation chamfering construction work, and has the advantages of being simple in structure and convenient to operate.