To provide an oblique positioning mechanism capable of accurately and easily positioning the oblique position of a cutter main body in order to solve the problem wherein the accurate positioning of the cutter main body can not easily be performed because the heavy cutter main body is finely adjusted directly by a user when positioned at a target oblique position in a circular saw constituted so as to incline the cutter main body left and right with respect to a material to be cut to perform the so-called oblique cutting.

An intermediate base 21 is held between the tilting support base 11 on the side of a table and a tilting base 12 on the side of the cutter main body in a relatively rotatable manner and a positioning screw 22 is brought into contact with the tilting support base 11 in a state that the intermediate base 21 is fixed to the tilting base 12 by a fixing screw 23 to set the oblique position of the cutter main body.