To reduce processing cost and parts cost by making unnecessary to use a female screw to a male screw portion formed on a rotation shaft.

A hinge mechanism 1 has a construction which provides a delayed operation by converting the rotating operation of a rotating shaft 4 coupled to the second hinge 12 into the operation in a linear direction. A rear end cylindrical portion 5c formed cylindrically near the rear end of the piston 5 is provided. At the rear end cylindrical portion 5c, one or more through-holes 5e are made in the peripheral wall portion, and a spherical body 6 which is exposed to the inside of the rear end cylindrical portion 5c and is able to contact a valley portion of the male screw portion 4b of the rotation shaft 4 is arranged in each through-hole 5e. Thus, the rotating motion of the rotation shaft 4 can be converted to the operation in a linear direction through the spherical body 6 without forming the female screw for the piston 5 arranged through a whirl-stop mechanism in the coupling cylindrical portion.