Whenever I want to eat burger when I am in/near Shinjuku station, here is the place I recommend, located on the 7th floor of the LUMINE Est (on top of Shinjuku Station East Exit). I recommend you try cheese burger, especially Mozzarella cheese burger, if you want taste the meat and bun. Coming drink and salad along with burger at the price of the burger during lunch time so try one for lunch.
Location
Tokyo-to, Shinjuku-ku, Shinjuku, 3 Chome-38-1 LUMINE Est 7F
TEL
03-3353-5071