diff --git a/src/main/java/org/embulk/input/sparql/SparqlInputPlugin.java b/src/main/java/org/embulk/input/sparql/SparqlInputPlugin.java
index b6041b4..abaf78c 100644
--- a/src/main/java/org/embulk/input/sparql/SparqlInputPlugin.java
+++ b/src/main/java/org/embulk/input/sparql/SparqlInputPlugin.java
@@ -155,7 +155,7 @@ private long getLongValue(QuerySolution solution, String column)
                 return literal.getInt();
             }
             else {
-                return Long.parseLong(literal.toString());
+                return Long.parseLong(literal.getLexicalForm());
             }
         }
         return Long.parseLong(solution.get(column).toString());
@@ -169,7 +169,7 @@ private double getDoubleValue(QuerySolution solution, String column)
                 return literal.getDouble();
             }
             else {
-                return Double.parseDouble(literal.toString());
+                return Double.parseDouble(literal.getLexicalForm());
             }
         }
         return Double.parseDouble(solution.get(column).toString());