A power plug conversion unit including a power plug conversion unit main body, a plurality of first plug pin insertion portions in which paired first plug pins of a power plug are respectively inserted, a plurality of conversion plug pins at least one of which moves in a direction orthogonal to a projecting direction, and an attaching and detaching mechanism configured to lock attachment and detachment of the first plug pins when the paired first plug pins are inserted into the first plug pin insertion portions, and release the lock of the first plug pins when at least one pin of the conversion plug pins is moved in the direction orthogonal to the projecting direction while the paired first plug pins are inserted in the first plug pin insertion portions.