Provided are a grip jacket which facilitates formation of a grip, is not easily separated, and is replaceable, and a grip for a cutting tool which exerts an excellent anti-slip effect, does not require insert molding, is low in cost, and is suitable for housing a folding blade as well. The grip jacket (10) to be mounted on a grip body to complete the grip for a cutting tool is made of an elastic body, and has a single-piece construction, with a pair of jacket side sections (110) interconnected by the intermediary of a jacket back section (120). Each jacket side section (110) has a thick-walled section (111) provided along an inner side of its open end (110c), and the thick-walled section (111) is provided with a fitting pocket (112) to be fitted with a fitting protrusion provided on the grip body side. The jacket back section (120) has, on its inner surface, a positioning protrusion (121) to be inserted into a fitting hole provided at the back section of the grip body for performing positioning.