He told reporters here that he did not want to disclose the reason for his quittingAIADMK.
But when reporters kept on asking him for the reason, he said "everything is obvious."
The resignation comes at a time when AIADMK general secretary V K Sasikala was elected as Legislature party leader at a meeting of legislature party meeting in Chennai earlier in the day.
Kannan joined AIADMK after quitting Congress on February 14 last year ahead of the Assembly polls.He enrolled himself as member of AIADMK then in the presence of then Tamil Nadu Chief Minister and AIADMK supremo Jayalalithaa at Chennai.