An Ni—Ti—Cu shape memory alloy electrothermal actuator element that recovers its original shape by electrical heating, having a wire diameter of 0.5 mm or less, comprising an Ni—Ti—Cu shape memory alloy wire which contains 49.0 to 51.0 at % of Ti, and 5.0 to 12.0 at % of Cu, with the balance being made of Ni, wherein the actuator element has a deterioration rate of shape strain recovery of 0.5% or less after repeating desired times of shape recovery movement.
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