The present invention relates to an azo compound represented by the following formula (1), [wherein, A represents a phenyl group which may have a substituent, R1 to R6 each independently represent a hydrogen atom, an alkyl group having a carbon atom number of 1 to 5, an alkoxy group having a carbon atom number of 1 to 5, a sulfo group, or an alkoxy group having a sulfo group and a carbon atom number of 1 to 5, and X represents an amino group which may have a substituent, a benzoylamino group which may have a substituent, a phenylamino group which may have a substituent, a phenylazo group which may have a substituent, or a naphthotriazole group which may have a substituent] or/and a salt thereof and to a polarizing film and a polarizing plate which contain it.