An electrorheological fluid is provided. The electrorheological fluid includes polarizing particles and a dispersion medium in which the polarizing particles are dispersed. The polarizing particles may include silica particles. The dispersion medium may include silicon oil. The silicon oil may be modified silicon oil including at least one functional group selected from the group consisting of a hydroxyl group (—OH group), an amine group (—NH2 group), a mercapto group (—SH group), and a carboxy group (—COOH group).