The present invention relates to a plug with connecting device, which comprises a top housing having a connecting device extended at one side for being connected to a power adapter; two copper contact rings; a retaining seat; an electrode sheet base having a pivotal shaft; two electrode sheets; and a bottom housing engaged with the top housing; when the two electrode sheets are longitudinally rotated, the two electrode sheets are enable to be pivotally moved at the outside of the bottom housing, and the two electrode sheets are positioned when being latched in the first positioning slot, an electrical conducting state is formed between the electrode sheets and the connecting device so as to transfer electric power to a power adapter.