Parallel connecting rod mechanism and connecting rod actuating device

In the parallel link mechanism (9), a tip-side link hub (13) is connected to a base-end-side link hub (12) via a three-link mechanism (14) so that the orientation thereof can be changed. Each link mechanism (14) has: a base-end-side end link member (15), one end of which is rotatably connected to a base-end-side link hub (12); a tip-side end link member (16), one end of which is rotatably connected to the tip-side link hub (13); and a center link member (17), both ends of which are rotatably connected to the other ends of the base-end-side and tip-end-side end link members (15, 16), respectively. In the three link mechanisms (14), a rotation transmission mechanism (42) is provided to each of two rotation mating parts (T3) and (T4) including both ends of a base-end-side and tip-end-side end link members (15, 16) and a center link member (17), said rotation transmission mechanism (42) being configured so that the rotation of one rotation mating part and the rotation of the other rotation mating part are reverse