The instant disclosure relates to an angle adjustable device, which includes: a base having a fixing member disposed thereon, where the fixing member has a fixing surface; a switch mechanism having a locking ring, a first gear, and a second gear, while at least one block protrudes from the inner surface of the locking ring, with the first gear having a contact incline slidingly abutted by the block, where the contact incline is defined with a first end and a second end, where the first gear is received by the locking ring and capable of meshing with the second gear; and a rotator having at least one connecting member connected to the second gear. The instant disclosure also discloses an electronic display unit using the same.