Abstract: A scissor includes a pair of handles and a pair of cutting blades. Each of the handles is formed with a recess that extends longitudinally at the inner portion from the front end of the handle to a point adjacent the rear end of the same. The handles are connected pivotally at the front end. The cutting blades are in superposed contact with each other when the scissor is closed. The cutting blades are connected pivotally adjacent to rear ends thereof and can be retracted into the recesses of the handles. A slide unit is connected to the cutting blades and is operated so as to extend or retract the cutting blades into the recesses. The slide unit engages one of first and second rounded protrusions on the handles to retain releasably and selectively the cutting blades in the fully extended and fully retracted positions. A spring unit is provided in the recess of each handle to bias the cutting blades toward each other in order to close automatically the scissor after a cutting operation has been accomplished.