Is a C# static method's variable initialised every time the method is called?

In the example below, will a new StringBuilder(255) be created every time the static Flog.Log() function is called, or will it only be created the first time the method is called?

public class Flog {

    public static void Log(FlogType flogType, string msg, params System.Object[] p) {

        StringBuilder sb = new StringBuilder(255);
        sb.Length = 0;
        sb.AppendFormat(msg, p);
        Log(flogType, sb.ToString());
    }
}