Question: Recently, I find out that somebody uses my network traffic. I found his `MAC` address and now I wanna find full details of his device. I tried: <http://www.macvendors.com/> and such this, but the response was only the name of manufacture. Tnx from anybody who helps me( or says a better solution to find him:) )
EDIT: Anybody who has another way to find him, tells me.

Answer: 
Just searching on the MAC will only give you the vendor. It will never show you in which hardware the component with the MAC was used. (Think of it as finding the vendor name for a lightbulb, which does not tell you in which device the bulb was used).

But given that you have the MAC and almost certainly the IP, you can use tools like nmap to find out more. If you do not like command line tools then try [the zenmap wrapper](https://nmap.org/zenmap/) around nmap. This usually will tell you which OS the device is running. That way you have a good idea if it is a phone (windows CE, android, ios or a PC (linux, BSD, windows).

Once you know that you can start to refine. E.g. if it turns out to be a windows device try `\\ip\c$`.
It is not possible to get device details via MAC address as @Hennes already said as the MAC address is only specific to the network card.

Another way to obtain more information is to log into your router/firewall and look for known devices with the found MAC. There you have the association MAC <-> IP address. 

You the can use tools like nmap/zenmap to gather more information.

If you are just after locking him/her out of your network it may be possible (depending on your router) to block access for the device with the specific MAC address.