Unfortunately Midori web browser lacks of this feature out of the box, but as mentioned on the official faqs we can found a workaround.
Install tsocks:
user@user-laptop:~$ sudo apt-get install tsocks
Edit the /etc/tsocks.conf file:
user@user-laptop:~$ sudo vi /etc/tsocks.conf
Edit in this way :
# Default server
# For connections that aren't to the local subnets or to 150.0.0.0/255.255.0.0
# the server at 192.168.0.1 should be used (again, hostnames could be used
# too, see note above)
server = 127.0.0.1
# Server type defaults to 4 so we need to specify it as 5 for this one
server_type = 5
# The port defaults to 1080 but I've stated it here for clarity
server_port = 1080
In this example configuration the proxy server is the localhost, the proxy server is a Sock5 and the localhost port is 1080 (you can change port number how you prefer)
Then launch midori in this way from terminal:
user@user-laptop:~$tsocks midori
Thats all