Their is no direct way to transfer bitcoins into bank. Nor banks accept bitcoins but via the third part exchange service you can buy and sell the Bitcoins to your bank account. most common website for exchange - www.Localbitcoins.com . Beware while choosing your trading partner.
Note they charge deposit fees when your transfer bitcoins to your localbitcoins account. I am suing this site from 2 years without any issue. in case any issue localbitcoins team helps you.