An electron gun for color picture tube wherein a focusing electrode adjacent to an acceleration electrode supplied with highest voltage includes two members comprising a first member and a second member, wherein a platelike correction electrode extended into the inside of the first member through a single opening formed in an end face of the first member opposed to the second member is so disposed above and below electron beam passage holes formed in an end face of the second member located at the opposite side with respect to the accelerating electrode and opposed to the first member as to be electrically in contact with the second member, wherein constant voltage is applied to the first member, and wherein voltage so changed in synchronism with electron beam deflection as to have a value increased with increase in the amount of deflection is applied to the second member.