string url = @”http://～”;

NetworkCredential credentials =
　　new NetworkCredential(
　　　　userName: @”～”,
　　　　password: @”～”,
　　　　domain: @”～”);

// 資格情報格納クラス
CredentialCache cache = new CredentialCache();
cache.Add(
　　uriPrefix: new Uri(uriString: url),
　　authType: @”NTLM”,
　　cred: credentials);

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Credentials = cache;

request.AllowAutoRedirect = true;
request.CookieContainer = new CookieContainer(capacity: 5);

using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
{
　　Console.WriteLine(@”In”);
}

Console.WriteLine(@”Done”);
Console.ReadLine();