The invention belongs to the technical field of traditional mechanical manufacture and especially relates to a thin-wall small-diameter round hole drilling and cutting device. The device solves the problem about cutting of a small hole with the diameter of 10mm or below or small gaskets with different usages on a thin-wall material. The diameter of the outer surface of a cutter disk is equal to the inner diameter of a bearing inner ring; the cutter disk is placed into a bearing hole; an axially disposed square hole is formed in the cutter disk; two radial threaded holes with the same horizontal height are formed in two sides of the cutter disk respectively; the threaded holes communicate with the square hole; a long fastening screw and a short fastening screw are installed in the threaded holes which are located in two sides of the cutter disk respectively; an adjustment sheet and a cutter blade are installed in the square hole of the cutter disk; the adjustment sheet and the cutter disk have the same height; the part of the cutter blade higher than the cutter disk stretches into an axial inner hole of a rotation shaft; an elastic cushion with a center hole is pasted on the lower surface of the cutter disk; a dividing ruler is disposed inside the center hole of the elastic cushion and at the position parallel to the square hole edge in the cutter disk; the rotation shaft is fixed above the cutter disk surface inside the bearing hole; and the rotation shaft is concentric with the cutter disk and a bearing. According to the invention, the problem that thin-wall small hole cutting can hardly be achieved can be solved.