Polyamideimide resin and optical member including polyamideimide resin

An object of the present invention is to provide a polyamideimide resin for an optical member having both high flexibility and bending resistance, and in particular, a polyamideimide resin for a front plate of an image display apparatus, and an optical member such as a front plate containing the polyamideimide resin.A polyamideimide resin having constitutional units represented by formula (1) and formula (2):in formula (1) and formula (2), X and Z each independently represent a divalent organic group,Y represents a tetravalent organic group, andat least a part of Z is constitutional unit represented by formula (3):in formula (3), R1 to R8 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R1 to R8 may be each independently substituted with a halogen atom,A represents -O-, -S-, -CO- or -NR9-, and R9 represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom,m is an integer of 1 to 4, and* represents a bonding hand.