diff --git a/src/main/java/w2phtml/rdf/DocumentPart.java b/src/main/java/w2phtml/rdf/DocumentPart.java
index 46ec8dd..d05e839 100644
--- a/src/main/java/w2phtml/rdf/DocumentPart.java
+++ b/src/main/java/w2phtml/rdf/DocumentPart.java
@@ -65,13 +65,12 @@ public class DocumentPart {
 				if (metaElements.hasAttribute("name") && metaElements.hasAttribute("content")) {
 					String metaName = metaElements.getAttribute("name");
 					String metaValue = metaElements.getAttribute("content");
-					if (metadata.containsKey(metaName)) {
-						metadata.get(metaName).add(metaValue);
-					} else {
+					if (!metadata.containsKey(metaName)) {
 						Set<String> names = new HashSet<String>();
-						names.add(metaValue);
 						metadata.put(metaName, names);
 					}
+					Set<String> names = metadata.get(metaName);
+					names.add(metaValue);
 				}
 			}
 		}