To provide a method for recovering a substrate with good productivity and good profitability under a condition where it can be reused as a raw material of the substrate for a recording material from the recording material on which a coating film is formed by using a natural polymer binder and a synthetic polymer binder on the substrate.

In the method for recovering the polyester resin substrate wherein the polyester resin substrate is recovered by treating a chip-like recording material having a coating film on the polyester resin substrate with an alkaline treating liquid in a treating tank, the treating tank has an ultrasonic oscillation generating means at least at one position, and a place through which the recording material passes within a range of ≤200 mm from the ultrasonic oscillation generating means, and an ultrasonic oscillation with a frequency of 20-40 kHz and an output of 0.1-2,000 W is generated from the ultrasonic oscillation generating means, and after the coating film is separated and removed from the recording material, the polyester resin substrate is recovered.