Novel ionic liquids containing alkali metal ions as component were prepared by the neutralization of N-ethylimidazole with various kinds of hydrogen sulfates (MHSO4; M = Li, Na, or K). All salts were obtained as transparent viscous liquids at room temperature. These ionic liquids showed ionic conductivity higher than 10(-4) S cm(-1) at room temperature, reflecting low glass transition temperature of below -60degreesC. This is the first report on alkali metal salts which are inherently liquid state at room temperature.