A cutting knife allows multiple different blade tips to be removably attached to a handle. The handle may be a pen-type handle that uses an activation button to move a spring-loaded plunger between an extended and a retracted position, typically using a cam and cam follower. The interchangeable blade tips may use spring-loaded cutting blades that retract, and preferably lock, within a sheath when a plunger is not pushing the blade into an extended position. Thus, the cutting blade is safely stored within the sheath when the plunger is retracted, as well as when the interchangeable blade tip is detached from the handle. The interchangeable blade tips may be disposable or reusable. The cutting knife may be configured as a surgical scalpel in which the cutting blade is a scalpel blade. In such applications, the pen-type handle may be of autoclavable materials so that it may be reusable after sterilization.
