A portable electronic device includes a first housing, a second housing detachably latched to the first housing through a latching tab, and a releasing mechanism. The releasing mechanism includes a button, an elastic member, and a shaft. The button surrounds the shaft and is rotatably assembled to the first housing by the shaft. The elastic member is coiled around the shaft and elastically resists the button to apply an elastic force to enable the button resisting the first housing. When the button rotates about the shaft under a pressure overcoming the elastic force, the latching tab is pushed to release the latching tab and the second housing.