Abstract: An elastic hinge that can make the earpiece extend outwards includes a slingshot case secured to an earpiece and slingshot core secured to a frame. The slingshot case has an installation hole, into which the slingshot core is inserted and fixed. The slingshot core has an installation base and central spindle which is fixed onto the installation base and extends inside the installation hole. A fixed tube and a spring are provided on the spindle, and a stopper is provided to stop the spring and fixed tube from coming apart. A pair of barbs, which are elastic and able to retract or dilate, are provided on the fixed tube, and which interact with a ring inside the installation hole. When the fixed tube passes through the ring, the barbs retract and then extend outwards to thereby connect the slingshot core and slingshot case.