\documentclass[dvipdfmx]{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[
grow'=right,
foo/.style={fill=black!30,inner sep=1mm}
]
\node[foo] {\textit{*****}} [sibling distance=3cm]
child {
node {\textit{0****}} [sibling distance=0.5cm]
child { node {\textit{00***}} }
child { node {\textit{01***}} }
child { node {...} }
child { node {\textit{09***}} }
}
child {
node {\textit{1****}} [sibling distance=0.5cm]
child { node {\textit{10***}} }
child { node {\textit{11***}} }
child { node {...} }
child { node {\textit{19***}} }
}
child {
node {\textit{2****}} [sibling distance=0.5cm]
child { node {\textit{20***}} }
child { node {\textit{21***}} }
child { node {...} }
child { node {\textit{29***}} }
}
child {
node[foo] {\textit{3****}} [sibling distance=2.5cm]
child {
node {\textit{30***}} [sibling distance=0.5cm]
child { node {\textit{300**}} }
child { node {...} }
child { node {\textit{309**}} }
}
child {
node[foo] {\textit{31***}} [sibling distance=0.5cm]
child {
node {\textit{310**}}
}
child {
node {\textit{311**}}
}
child {
node {\textit{312**}}
}
child {
node {\textit{313**}}
}
child {
node[foo] {\textit{314**}} [sibling distance=0.5cm]
child {
node {\textit{3140*}}
}
child {
node [foo] {\textit{3141*}}
child {
node {\textit{31410}}
}
child {
node {\textit{31411}}
}
child {
node {\textit{31412}}
}
child {
node {\textit{31413}}
}
child {
node {\textit{31414}}
}
child {
node[foo] {\textit{31415}}
}
}
}
}
};
\end{tikzpicture}
\end{document}