diff --git a/src/UserFnExecutor.js b/src/UserFnExecutor.js
index 9e7ffaf..0f54341 100644
--- a/src/UserFnExecutor.js
+++ b/src/UserFnExecutor.js
@@ -10,6 +10,9 @@ module.exports = function UserFnExecutor(user_function) {
         var result;
         try {
             result = user_function.apply(self, self.args.map(f => f.calc()));
+            if (result instanceof Error) {
+                throw result;
+            }
         } catch (e) {
             const errorValue = getErrorValueByMessage(e.message)
             if (user_function.name === 'is_blank'
diff --git a/test/5-formulajs-tests.js b/test/5-formulajs-tests.js
index bfa75a6..91b4481 100644
--- a/test/5-formulajs-tests.js
+++ b/test/5-formulajs-tests.js
@@ -32,4 +32,15 @@ describe('formulajs integration', function() {
             assert.strictEqual(XLSX_CALC.xlsx_Fx.TRUNC === formulajs.TRUNC, true);
         });
     });
+    describe('UserFnExecutor()', function() {
+        it('handles error that is returned instead of thrown', function() {
+            XLSX_CALC.import_functions(formulajs);
+            var workbook = {};
+            workbook.Sheets = {};
+            workbook.Sheets.Sheet1 = {};
+            workbook.Sheets.Sheet1.A2 = {f: 'AVERAGE(A1)'};
+            XLSX_CALC(workbook);
+            assert.strictEqual(workbook.Sheets.Sheet1.A2.w, '#DIV/0!');
+        });
+    })
 });