A shape memory alloy actuator system includes a shape memory alloy actuator, a mobile object, an elastic member, a first regulating member, and a second regulating member, a detecting section which detects a resistance value of the shape memory alloy wire, a calculating section which calculates an electric current applied, an output section, a control section which controls the detecting section, the calculating section, the output section. The calculating section calculates a first resistance value at which, a proportion of a resistance change with respect to a change in a unit temperature changes from a first proportion to a second proportion which differs from the first proportion, and the control section carries out a position control of the shape memory alloy actuator by the first resistance value, when the shape memory alloy wire is to be elongated.