A process is provided for producing an ethylene/vinyl alcohol copolymer by which impurities such as catalyst residue and by-products and solvent are removed to a high degree. A high-quality, homogeneous product can be efficiently produced by including a washing step including: introducing a paste containing an ethylene/vinyl alcohol copolymer and an alcohol into a washing tank; applying a shear force to the paste to knead the paste while contacting the paste with washing water so that a surface of the paste is repeatedly displaced by an inner part thereof; and discharging the alcohol to an outside of the tank together with the washing water to obtain a water-containing ethylene/vinyl alcohol copolymer composition having a small alcohol content.