[Problem]
To provide a polyurethane elastic fiber with excellent spinnability, stretchability, thermal adhesion, and unwinding properties, and a production method therefor.
[Solution]
A polyurethane elastic fiber having as a main component a polyurethane whose main starting materials are a polymer diol and a diisocyanate, wherein the polyurethane elastic fiber contains the three components in (a) through (c) below.



(a) A thermoplastic polyurethane elastomer
(b) A rosin and/or derivative thereof
(c) A cellulose ester and/or derivative thereof