The present invention relates to a thin slide mechanism that can be incorporated in a portable electronic device. A slide unit mechanism having: a plate 1 of a quadrangular shape in a plane view in which a protruding portion A is formed in a sliding direction in the center of the rear surface and receding portions B are formed in two locations respectively to the left and to the right of the protruding portion; two sliding members 2 slidably joined to both ends of the plate; and a linking member 22 that integrally links the two sliding members on the front surface side of the plate and has a width substantially equal to or less than a longitudinal width of the sliding member in the sliding direction, wherein the entire portion or a part of the rear surface portion of the folded sliding member, when folded to the rear surface, is extended to serve as stopper portions 3, a torsion spring is arranged in each of the left and right receding portions of the plate, one end of each torsion spring is locked to the substantially central portion, in the sliding direction, of the side surface of the protruding portion formed on the plate, the other end of each torsion spring is locked to the stopper portions of the sliding members, connection members for connection to a housing are formed at the approximately four corners of the plate, and sliding ends are formed when the connection members and the stopper portions of the sliding members abut on each other.