diff --git a/src/STEPControl/STEPControl_ActorWrite.cxx b/src/STEPControl/STEPControl_ActorWrite.cxx
index 6a6ee5b351..a1de838efe 100644
--- a/src/STEPControl/STEPControl_ActorWrite.cxx
+++ b/src/STEPControl/STEPControl_ActorWrite.cxx
@@ -1315,7 +1315,9 @@ Handle(Transfer_Binder) STEPControl_ActorWrite::TransferCompound (const Handle(T
           NonManifoldGroup->Append(aSubShell);
         }
       } 
-      else if (!isManifold && (aSubShape.ShapeType() == TopAbs_SHELL) ) {
+      else if (!isManifold &&
+               (aSubShape.ShapeType() == TopAbs_SHELL || aSubShape.ShapeType() == TopAbs_FACE))
+      {
         RepItemSeq->Append(aSubShape);
         NonManifoldGroup->Append(aSubShape);
       }
diff --git a/tests/bugs/step/bug31485 b/tests/bugs/step/bug31485
new file mode 100644
index 0000000000..db3cc1826e
--- /dev/null
+++ b/tests/bugs/step/bug31485
@@ -0,0 +1,15 @@
+puts "====================================================================="
+puts "OCC31485: Export STEP in nonmanifold mode looses all faces except one"
+puts "====================================================================="
+puts ""
+
+brestore [locate_data_file bug31485.brep] a
+
+param write.step.nonmanifold 1
+
+testwritestep comp_nonmanifold.step a
+testreadstep comp_nonmanifold.step result
+
+checkshape result
+
+checknbshapes result -face 3