A CMP slurry is mixed with an oxidant in polishing and contains a copper rust inhibitor, a water-soluble polymer, a pH controller capable of forming a complex with copper, and water, and is substantially free from abrasive. The CMP slurry effectively reduces dishing in chemical polishing of copper and forms reliable wiring. Preferably, the contents of the rust inhibitor, the water-soluble polymer, and the oxidant are 0.1 to 5 wt %, 0.05 to 5 wt %, and 0.01 to 5M relative to 1 liter of the CMP slurry, respectively, and the amount of the pH controller is a necessary amount for adjusting pH of the CMP slurry to 1.5 to 2.5.