A shape-memory alloy valve device includes a shape-memory alloy wire configured to make a valve member perform an opening/closing operation and a valve actuation control unit configured to control an opening/closing operation of the valve member. The valve actuation control unit controls energization of the shape-memory alloy wire in accordance with an input valve open signal or an input valve close signal so as to make the shape-memory alloy wire contract by raising a temperature of the shape-memory alloy wire beyond an operating environmental temperature, thereby controlling valve opening/closing. A preheating unit heats the shape-memory alloy wire to a preset preheat set temperature by energizing the shape-memory alloy wire from a power circuit when the temperature of the shape-memory alloy wire which is measured by a temperature measurement unit is lower than the preheat set temperature.