Python 2, 156156 151151 147147 141141 139
edit 1: edited to use input() instead of a function.
edit 2: used str.join and added to var c to remove some redundant characters.
edit 3: removed some unnecessary string escape sequences.
edit 4: used ~-n instead of a=n-1
This was good fun to program, my first code golf!
n=input() a='/\/ '*~-n b='\ '+'\/\ '*~-n+'\\' c='\n| '+a+'/\ |\n| \/ '+a+'|' print'\n '.join((' __'*n,'/ \\'*n+c,b+'/','/'+b+c,'\__/'*n)) save it in an external text editor as n.py in order to remove last newline character in order to reduce file size by 1 byte, run the module, and input your number.