A fluid valve drive mechanism provided with a drive means and an emergency drive means. The emergency drive means comprises an upper support section connecting to the drive means and ascending and descending, a lower support section connecting to a valve element, a spring provided between both the support sections, and an emergency cancelling unit capable of fixing the distance between the upper support section and the lower support section. The upper support section is caused to descend by the drive means from an initial state in which the valve element is in contact with a valve seat and the spring is compressed by a predetermined length between both the support sections. This compresses the spring to a predetermined length, and after that, the distance between the upper support sectionand the lower support section is fixed by the emergency cancelling unit. With the spring kept compressed between the upper support section and the lower support section, opening and closing of the valve is controlled by causing the valve element to ascend and descend by the drive means. In an emergency case, the emergency cancelling unit is released to allow the spring to stretch to drive the fluid valve as an emergency measure.