The present invention provides a method for producing a polymer by efficiently removing residue of metals such as titanium, aluminum and lithium from a polymer solution containing the residue of these metals to successfully obtain a purified polymer solution containing a smaller amount of the metal residue and having satisfactory color tone and transparency, a polymer solution and a polymer obtained by the production method. The method for producing a polymer of the present invention includes, step 1 of preparing a polymer solution containing one or more metals selected from the group consisting of aluminum, lithium and titanium; and step 2 of obtaining a solution mixture by mixing the polymer solution and water in a volume ratio of 0.1 to 10 relative to the polymer solution, wherein in the step 1, when the aluminum content in a polymer contained in the polymer solution is less than 30 ppm, the pH of the water phase of the solution mixture is controlled to be 10 or less in the step 2, and in the step 1, when the aluminum content in the polymer contained in the polymer solution is 30 ppm or more and 200 ppm or less, the pH of the water phase of the solution mixture is controlled to be 5.5 or less, or 7 to 10 in the step 2.