Thermoplastic resin and optical member

Provided are: a thermoplastic resin capable of balancing a high refractive index, high heat resistance, and low birefringence; and an optical member comprising the thermoplastic resin. This thermoplastic resin contains a repeating unit represented by formula (1). (In formula (1), rings Z (identical or different) represent a polycyclic aromatic hydrocarbon in which three or more benzene rings are bonded, R1, R2, R3, and R4 each independently represent a hydrogen atom or a halogen atom, or represent a C1-20 substituent which may include an aromatic group, L1 and L2 each independently represent a divalent linking group, j and k each independently represent an integer of 1 or more, m and n each independently represent 0 or 1, and n each independently represents an integer of 1 or more. W represents at least one group selected from the group consisting of groups represented by formula (2) or (3) (In formula (3), X represents a divalent linking group). # imgabs0 # 本发明提供能够使高折射率、高耐热性、低双折射平衡的热塑性树脂和包含该热塑性树脂的光学部件。本发明的热塑