diff --git a/contrib/utilities/astyle.rc b/contrib/utilities/astyle.rc
new file mode 100644
index 0000000..39b789c
--- /dev/null
+++ b/contrib/utilities/astyle.rc
@@ -0,0 +1,15 @@
+# astyle indentation style for FDPS SPH
+# Run astyle on all files with:
+#    astyle --options=contrib/utilities/astyle.rc `find src | egrep '\.(h|cc)$'`
+
+--style=google
+
+# use tabs:
+--indent-preprocessor
+--indent=tab
+--indent-namespaces
+--indent-labels
+
+--max-instatement-indent=80
+--suffix=none
+--quiet
diff --git a/contrib/utilities/indent b/contrib/utilities/indent
new file mode 100755
index 0000000..af0ded0
--- /dev/null
+++ b/contrib/utilities/indent
@@ -0,0 +1,29 @@
+#!/bin/bash
+
+if test ! -d src ; then
+  echo "*** This script must be run from the top-level directory of FDPS SPH."
+  exit
+fi
+
+if test ! -f contrib/utilities/astyle.rc ; then
+  echo "*** No style file doc/astyle.rc found."
+  exit
+fi
+
+if test -z "`which astyle`" ; then
+  echo "*** No astyle program found."
+  exit
+fi
+
+if test "`astyle --version 2>&1`" != "Artistic Style Version 3.1" ; then
+  echo "*** Found a version of astyle different than the required version 3.1."
+  exit
+fi
+
+
+echo "--- Indenting all FDPS SPH files"
+
+find src \( -name '*.cc' -o -name '*.h' \) -print | xargs -n 50 -P 10 astyle --options=contrib/utilities/astyle.rc
+
+# remove execute permission on source files:
+find src \( -name '*.cc' -o -name '*.h' \) -print | xargs -n 50 -P 10 chmod -x