A sectioning instrument fabricates a section having an accurate and uniform thickness to be carried to a next step automatically without deforming a surface of an embedded block and while observing the surface of the embedded block. The sectioning instrument includes a sample base for fixing an embedded block, a cutter for fabricating a section by sectioning the embedded block, a carrier for carrying the section, and a feed mechanism for moving the sample base in a predetermined feed direction. The carrier includes a belt, a direction switching portion provided on an upper side of the cutter, and a rear roller. The belt is inserted to between the cutter and the direction switching portion from a rear side of the cutter, folded back to an upper side by the direction switching portion and is reeled back to the rear side of the cutter by the rear roller substantially in parallel with the feed direction of the feed mechanism in a plane view.