PURPOSE: To store a plate-shaped body compactly by opposing an hinge plate having the same apex angle as the angle of the folding line of 'Miura folding' to a hinge plate having another apex angle, and placing hinges at the hinge plates.

CONSTITUTION: A hinge mechanism A for use in folding a plate-shaped body such as a parabola antenna for space communications or a marine structure is constructed by using 'Miura folding' which is one kind of the way of the art of folding paper; i.e., a hinge plate 1 having an apex angle of 180°-α and a hinge plate 2 having another apex angle α are opposed to each other. The hinge pieces 3a, 4a of plural hinges 3, 4 are secured to the two sides of the hinge plate 1 which sandwich the apex angle 180°-α. Similarly, the hinge pieces 5a, 6a of plural hinges 5, 6 are secured to the two sides of the hinge plate 2 which sandwich the apex angle α. Thereby the hinges are substituted for the folding lines of the 'Miura folding' to achieve compact storage.