Disclosed is a thin film circuit substrate and a manufacturing method thereof, which are capable of forming a pattern having a feature size of less than 10 μm by forming a seed layer and a plating layer on a base substrate and then forming, through electrospinning, a photoresist layer having a thickness in a set range. The disclosed thin film circuit substrate comprises: a base substrate; a thin film seed layer formed on the top surface of the base substrate; a metal layer formed on the top surface of the thin film seed layer; and a photoresist layer formed on the top surface of the metal layer, wherein the thickness of the photoresist layer is in a range of 1 μm to 5 μm.