\documentclass[12pt,a4paper]{article}
\setlength{\topmargin}{20mm}
\addtolength{\topmargin}{-1in}
\setlength{\oddsidemargin}{20mm}
\addtolength{\oddsidemargin}{-1in}
\setlength{\evensidemargin}{15mm}
\addtolength{\evensidemargin}{-1in}
\setlength{\textwidth}{170mm}
\setlength{\textheight}{254mm}
\setlength{\headsep}{0mm}
\setlength{\headheight}{0mm}
\setlength{\topskip}{0mm}
\usepackage{xltxtra}
\setmainfont{IPAPMincho}
\setsansfont{IPAPGothic}
\setmonofont{IPAGothic}
\XeTeXlinebreaklocale "ja"
\usepackage{xeCJK}
\usepackage{hyperref}
\usepackage{listings}
\usepackage{verbatim}
\usepackage{graphicx}
\usepackage{float}
\title{title}
\author{author}
\date{\today}
\begin{document}
\maketitle
\end{document}