Microwave oven with bread toaster

Disclosed is a microwave oven having a toasting function and compact dimensions. The microwave oven comprises a cavity and a component chamber; a toaster case at a front of the component chamber and having an opening at a front thereof; a toaster door at a front of the toaster case for opening/closing the opening; a tray assembly installed in an interior of the toaster case for supporting at least one slice of bread; and a heater assembly installed in an interior of the toaster case, for heating the bread.