A cutter 1 is formed by detachably attaching a replaceable blade 3 to a cutter body 2. The cutter body 2 is configured to include a main body block 4 and a slide block 5. The main body block 4 includes a main body supporting section 41 that supports the back face of the replaceable blade 3, and a main body connecting section 42 that connects with the replaceable blade 3 from the front face side. The slide block 5 includes a rear side supporting section 51 that supports the back face of the replaceable blade 3, a slide connecting section 52 that connects with the replaceable blade 3 so as to retract the replaceable blade 3 toward the rear side, and a back side protruding section 53 that protrudes on the back side in a thickness direction X. In an attached state S, the replaceable blade 3 is elastically deformed to curve in the thickness direction, the slide block 5 is pressed toward a main body block 4 side in the thickness direction X by a elastic force of the replaceable blade 3, and the back side protruding section 53 is engaged with an engaged section 43 provided in the main body block 4.
