A key structure is provided, including a substrate, a key cap, a first link, and a second link pivotally connected to the first link. The first and second links movably connect the key cap with the base. The key cap comprises a first surface and a guiding portion extended along a first direction, wherein the guiding portion has a second surface. The first link is made of metal and has a sliding end forming a first curved portion and a second curved portion. The first and second curved portions are respectively adjacent to the first and second surfaces and slidable along the guiding portion.