Provided is a manufacturing method for a thin phosphor glass plate by which a thin phosphor glass plate can be more certainly produced. A manufacturing method includes the steps of: preparing a phosphor glass base material 21 having a first principal surface 21a and a second principal surface 21b opposed to each other; placing the phosphor glass base material 21 on a stage 22 and fixing the second principal surface 21b onto the stage 22; and polishing the first principal surface 21a of the phosphor glass base material 21 with a polishing member 23 including an abrasive layer 24.