Wall surface trepanning device

The invention provides a wall surface trepanning device. The wall surface trepanning device comprises a box body, an eccentric transmission shaft and a tool bit assembly. A limiting hole is formed in the first end of the box body; the size of the limiting hole is the same as that of a to-be-cut square hole; the eccentric transmission shaft is arranged in the box body and comprises a first shaft body and a second shaft body, and the axes of the first shaft body and the second shaft body are parallel. The first shaft body can rotate around the axis of the first shaft body; the tool bit assembly is arranged in the limiting hole and comprises a Reuleaux triangle block and at least one tool bit. The Reuleaux triangle block is rotationally connected with one end of the second shaft body, and the geometric center of the Reuleaux triangle block coincides with the axis of the second shaft body; and the blade contour of the tool bit coincides with the edge contour of the opposite angles of the Reuleaux triangle block.