Peripheral with pivotal turn-over guide mechanism

A peripheral with a pivotal turn-over guiding mechanism includes: a transporting mechanism; first to third passages; an image processing unit disposed on the first passage, wherein after the image processing unit performs a first image process on a first side of a medium, the transporting mechanism transports the medium into, partially out of and back into the second passage, into the third passage, and then into the first passage, and the image processing unit performs a second image process on a second side of the medium; and a guide member, which is rotatably disposed at a connection portion of the third passage, the second passage and the first passage, normally closes a forward path from the first passage to the second passage, and normally opens a reverse path from the second passage to the third passage.