A filter of an electronic display device provides a clear image, the filter comprising an squarylium compound represent by formula (II): ##STR00001## wherein R.sup.15 and R.sup.17 independently represent a hydrogen atom, a halogen atom, substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a nitro group, a cyano group, a hydroxyl group, a substituted or unsubstituted amino group, or a substituted or unsubstituted heterocyclic group; R.sup.16 and R.sup.18 independently represent an alkoxyalkoxyl-substituted alkyl group; R.sup.19 and R.sup.20 independently represent a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a nitro group, a cyano group, a hydroxyl group, a substituted or unsubstituted amino group, or a substituted or unsubstituted heterocyclic group; m represents an integer of 0 to 4, wherein, when m is 2 to 4, R.sup.19 may be the same or different, respectively; and n represents an integer of 0 to 4, wherein, when n is 2 to 4, R.sup.20 may be the same or different respectively.