PURPOSE: To improve the functions of valve opening regulation and emergency shut-out by a steam regulating valve control device for a steam turbine, particulary by an electric governor, by improving responsiveness thereof as well as forming it in a compact size.

CONSTITUTION: An oil pressure supplying circuit is formed in such constitution that an actuator 3 and a trip mechanism par 4 are integrated with a servo motor 1, while the actuator 3 is operated by a signal from an electric governor at the time of normal operation of a turbine, and a relay plunger 10 is moved in vertical direction through a linkage. An emergency switching valve 15 is operated at the time of turbine trip, so that the relay plunger 10 is moved upward so as to form a trip circuit. A piston 6 is slid in proper direction in respective cases, and a steam regulating valve 2 is opened/closed or closed fully.