To provide a foldable utility knife in which a blade may be easily folded into a handle, the blade is held securely, improved means are provided for replacing the blade, and which is simple to use and inexpensive to manufacture and maintain.

A utility knife 1 comprises a handle 2 and a blade holder 3 which is movably mounted on the handle for movement from an unfolded position to a folded position. The handle has a space to receive the blade holder when the blade holder is in its folded position. The blade holder has a blade holder mechanism and a finger support 80. And the handle also has a blade storage compartment 4.