Constant width of outline shader

I found shader script which generate outline: https://willweissman.wordpress.com/tutorials/shaders/unity-shaderlab-object-outlines/ But the main problem is that I expected constantly outline. I don't know what is the reason of increasingly enlarge outline when i moves camera. Here is the code: https://pastebin.com/aVyejxDb

I can not use simply outline shader because I am working on concave shapes

So, Could you know how to maintain constant outline width independently of camera moves?