Anion exchange membranes containing N-isopropylacrylamide as a component were prepared, and their electrochemical properties were examined. The membranes were crosslinked with ethylene glycol dimethacrylate and contained weakly basic or strongly basic anion exchange groups. The dependence of electrochemical properties of the membranes (electrical resistance, transport number of anions, water content, and reduced osmotic flux) on temperature was completely different from those of the anion exchange membrane without N-isopropylacrylamide. For example, the reduced osmotic flux decreased with increasing temperature until 40 degrees C, and the transport number of chloride ions increased with increasing temperature from 25.0 degrees C, although those of the conventional membrane monotonously increased or decreased. The transport numbers of various anions relative to chloride ions in electrodialysis were evaluated at a different temperature. Although the transport numbers between anions did not change appreciably in the conventional membrane with temperature, those of the anion exchange membranes with N-isopropylacrylamide changed with a temperature dependent on the hydration degree of anions: permeation of less-hydrated anions such as nitrate and bromide ions compared with chloride ions increased with increasing temperature, and that of strongly hydrated anions such as sulfate and fluoride ions decreased with increasing temperature. This is based on the increase or decrease in uptake of the anions in the membrane with the change in temperature because hydrophilicity of the membranes changes with temperature due to the apparent aggregation of isopropyl groups in the membranes. And the change in electrochemical properties and transport numbers of various anions relative to chloride ions with temperature was completely reversible with increasing or decreasing temperature.