THROTTLE VALVE

PROBLEM TO BE SOLVED: To provide a throttle valve having a stable pressure characteristic and easy to adjust pressure when a low-viscosity operating fluid is used. SOLUTION: This throttle valve is constituted of a female screw 11 and a male screw 12 coupled with each other, and a passage in which an operating fluid flows is formed with a gap 17 between the root 15 of the screw thread 13 of the female screw 11 and the crest 16 of the screw thread 14 of the male screw 12. A passage having a small cross sectional area and long distance can be realized for the passage of the operating fluid by this throttle valve. The effect of an abrupt pressure change at the inlet portion of a throttle valve, which becomes a problem when a low-viscosity operating fluid is used, can be made relatively small, thereby a stable pressure characteristic can be obtained even when the low-viscosity operating fluid is used. The pressure of this throttle valve can be finely adjusted easily by properly setting and changing the coupling length of the screws 11, 12.