To obtain an antidegradant and a thermoplastic resin composition which have excellent inhibitory performance against the degradation by the hydrolysis of condensation type thermoplastic resins, and a molded article of a thermoplastic resin which has excellent mechanical properties, surface state, and the like.

An aliphatic polycarbodiimide compound is incorporated into the antidegradant for the condensation type thermoplastic resin. Further, this antidegradant is incorporated into the thermoplastic resin composition. Furthermore, the molded articles can be obtained from the resin composition for molding which comprises this antidegradant and the condensation type thermoplastic resin.