diff --git a/doc/Makefile.am b/doc/Makefile.am
index 9f9c1eba..626ee9c6 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1,6 +1,4 @@
-if HAVE_SPHINXBUILD
 SUBDIRS = manual-src
-endif #SPHINXBUILD
 
 doc_xmlrpcdir = $(docdir)/xmlrpc
 dist_doc_xmlrpc_DATA = xmlrpc/aria2mon \
diff --git a/doc/manual-src/en/Makefile.am b/doc/manual-src/en/Makefile.am
index 87eb83bd..2883070e 100644
--- a/doc/manual-src/en/Makefile.am
+++ b/doc/manual-src/en/Makefile.am
@@ -16,8 +16,15 @@ man_MANS = $(BUILDDIR)/man/aria2c.1
 EXTRA_DIST = $(man_MANS) aria2c.rst libaria2.rst index.rst README.rst\
 	technical-notes.rst _static/default2.css mkapiref.py
 
+if HAVE_SPHINXBUILD
 $(man_MANS): aria2c.rst
 	$(MAKE) man
+else
+$(man_MANS):
+	$(warning Building only stub man pages. Please install sphinx-build)
+	if [ ! -d "$(@D)" ]; then mkdir -p "$(@D)"; fi;
+	if [ ! -e "$@" ]; then touch "$@"; fi;
+endif
 
 # Autogenerated rules by sphinx-quickstart
 
diff --git a/doc/manual-src/pt/Makefile.am b/doc/manual-src/pt/Makefile.am
index 3051fec2..2fd124ff 100644
--- a/doc/manual-src/pt/Makefile.am
+++ b/doc/manual-src/pt/Makefile.am
@@ -16,8 +16,15 @@ mandir = @mandir@/pt
 man_MANS = $(BUILDDIR)/man/aria2c.1
 EXTRA_DIST = $(man_MANS) aria2c.rst index.rst README.rst _static/default2.css
 
+if HAVE_SPHINXBUILD
 $(man_MANS): aria2c.rst
 	$(MAKE) man
+else
+$(man_MANS):
+	$(warning Building only stub man pages. Please install sphinx-build)
+	if [ ! -d "$(@D)" ]; then mkdir -p "$(@D)"; fi;
+	if [ ! -e "$@" ]; then touch "$@"; fi;
+endif
 
 # Autogenerated rules by sphinx-quickstart
 
diff --git a/doc/manual-src/ru/Makefile.am b/doc/manual-src/ru/Makefile.am
index 6b823e08..41ee6c58 100644
--- a/doc/manual-src/ru/Makefile.am
+++ b/doc/manual-src/ru/Makefile.am
@@ -16,8 +16,15 @@ mandir = @mandir@/ru
 man_MANS = $(BUILDDIR)/man/aria2c.1
 EXTRA_DIST = $(man_MANS) aria2c.rst index.rst _static/default2.css
 
+if HAVE_SPHINXBUILD
 $(man_MANS): aria2c.rst
 	$(MAKE) man
+else
+$(man_MANS):
+	$(warning Building only stub man pages. Please install sphinx-build)
+	if [ ! -d "$(@D)" ]; then mkdir -p "$(@D)"; fi;
+	if [ ! -e "$@" ]; then touch "$@"; fi;
+endif
 
 # Autogenerated rules by sphinx-quickstart