A dual directional sliding hinge is mounted in a portable device with a cover, a first base and a second base and has a main panel, a first sliding unit, a second sliding unit. The main panel is attached to the cover. The first sliding unit is attached to the first base. The second sliding unit is attached to the second base. When the first and second sliding units slide at the closing position, the cover and the first and second bases are folded to have a smallest volume. Since the first and second sliding units have different sliding distances when sliding to different directions, the functioning units on the first and second bases are revealed alternatively. Therefore, the user can decide to use different functioning units as desired.