A support apparatus for an insulator arm is disclosed. The support apparatus for an insulator arm in accordance with an embodiment of the present invention includes: a first key cap connector and a second key cap connector coupled, respectively, with a first insulator arm and a second insulator arm that are divided, respectively, from a pair of insulator arms; a Y-shaped saddle coupled with the first key cap connector and the second key cap connector; and an insulator arm support metal fitting coupled with the Y-shaped saddle and connecting the pair of insulator arms with each other.