Utility knife

An utility knife comprising:

• a housing having a chamber, an opening formed at an end of the chamber, and a switch slot communicating with the chamber;
• a blade seat arranged in the chamber and having a blade holding slot and a guiding slot communicating with the blade holding slot;
• a blade detachably mounted to the blade holding slot and having at least one engaging slot;
• and
• a switching assembly including a toggle switch movably arranged to the switch slot and exposed to the housing, an engaging block disposed at an end of the toggle switch and movably arranged to the guiding slot, and a biasing member elastically biasing the engaging block relative to the guiding slot, and wherein the toggle switch is configured to drive the engaging block to move relative to the guiding slot, so that the engaging block is detachably engaged with the at least one engaging slot of the blade.