A utility knife comprises a housing (1), a blade carrier (2), a blade (3), a position control component (4) and a safety control component (5); a positioning direction (B) is defined at an angle to the sliding direction (A) of the position control component (4), the first blocking position (141) is farther away from the positioning portion (42) of the position control component (4) than the rest areas of the slide rail (13) except the first blocking position (14). In this way, in addition to blocking position shift, the position control component can also be used for contact-fitting with the blade carrier to determine whether the blade carrier can slide forward independently. Therefore, the utility knife has fewer components, resulting in low material cost, fewer assembly steps, convenient and time-saving assembly process, and the components are not easy to lose.