diff --git a/Makefile b/Makefile
index 8dd56e7d..e193a9bb 100644
--- a/Makefile
+++ b/Makefile
@@ -5,4 +5,5 @@ install:
 	bash install.sh
 
 share/man/man1/%.1: share/man/man1/%.1.adoc bin/ruby-build
+	which asciidoctor || gem install asciidoctor
 	asciidoctor -b manpage -a version=$(release_version:v%=%) -o $@ $<