A power adapter is disclosed. The first guiding slot of the movable member is inserted with the shaft rod of the plug assembly, and the crack arm performs a rotation around a fixed axis about the shell. Additionally, the second guiding slot of the movable member and the post of the socket assembly are embedded for sliding. The movable member slides in two different directions to drive the socket assembly performing an ascending and lowering movements in a vertical direction, and the plug assembly is driven to rotate around a fixed axis at the same time. Thereby, the overall height is reduced to facilitate storage and carry; additionally, each pin can be stored in the shell to prevent the bag from being pierced and prevent other items in the bag from being scratched.