A cutter 1 is configured by detachably attaching a replaceable blade 3 to a cutter body 2. The cutter body 2 is configured of a main body block 4 and a slide block 5. The main body block 4 includes a container section that houses the slide block 5, a main body supporting section that supports a back face of the replaceable blade 3, and a main body connecting section 42 that connects with the replaceable blade 3 from a front face side. The slide block 5 includes a rear-side supporting section, a slide connecting section 52, a flexible section 53, and a wing section 56. A front side retaining section 43 that retains the wing section 56 from a front side is formed in at least one side of the container section 45 in a height direction Z, and the front side retaining section 43 includes a protruding engaging section. In an attached state S, the wing section 56 is engaged from a foreside by the protruding engaging section, and the wing section 56 is configured capable of being released from the protruding engaging section by bending the flexible section 53 of the slide block 5 from the attached state S.
