Disclosed is a foldable electronic device including a flexible display, a first housing and a second housing, a hinge housing, and a hinge structure. The hinge structure includes a first rotary member coupled to the first housing, a second rotary member coupled to the second housing, a first arm part coupled to the first rotary member and including a first rotary cam, a second arm part coupled to the second rotary member and including a second rotary cam, a fixed cam part including a first fixed cam engaged with the first rotary cam, a second fixed cam engaged with the second rotary cam, and a cam body connecting the first fixed cam and the second fixed cam, a stopper that restricts rotational angles of the arm parts, and an additional structure disposed between the stopper and the fixed cam part.