diff --git a/sphinx_d2lang/d2lang.py b/sphinx_d2lang/d2lang.py
index 4cb7df1..f75ced8 100644
--- a/sphinx_d2lang/d2lang.py
+++ b/sphinx_d2lang/d2lang.py
@@ -33,7 +33,12 @@ class D2langDirective(SphinxDirective):
         if self.arguments:
             path = Path(srcdir + '/' + self.arguments[0])
             if path.is_file():
-                build_svg(self.arguments[0], srcdir, output_fname, layout)
+                build_svg(
+                    srcdir + '/' + self.arguments[0],
+                    srcdir,
+                    output_fname,
+                    layout
+                )
             else:
                 raise
         else: