PURPOSE: To obtain an excellent display quality disappearing generation of a yellow colored deposit by filling up an electrochromic solution contg. a viologen and a cyclodextrin as a active substance and a ferrocyanide ion as a supplementary oxidation reduction substance and an electrolyte between counter electrodes in which at least one of the electrodes is a display electrode.

CONSTITUTION: Said viologen comprises a viologen generating the yellow colored deposit such as a heptyl viologen shown by formula I namely, N,N'- diheptyl-4,4'-bipyridium salt as an lakylviologen. Said cyclodextrin (CD) comprises α-CDWγ-CD having 6W8 numbered glucopyranose rings in the chemical structure shown by formula II. Said ferrocyanide ion in the supplementary oxidation reduction system comprises for example, potassium ferrocyanide, and sodium ferrocyanide. Said electrolyte comprises a hypophosphrous acid ion such as sodium hypophosphite or potassium hypophosphite. By incorporating CD to the electrochromic solution, the generation of yellow deposit may be avoided or reduced.