An output mode switching apparatus including a power unit, a hammering unit, an output shaft, a housing, and a shifting member is provided. The hammering unit includes a gasket cup, a switching ring, a spring member, a hammering seat, and a main shaft. When the power unit is not in operation, the switching ring is restricted so as to be positioned against and secured to the gasket cup. When the mains shaft is driven by the power unit to rotate, the hammering seat is carried to rotate and is applied with a restriction for restricting the hammering seat from axial movement, thus configuring an output mode of electric drill. When the shifting member is turned, the restriction applied to the hammering seat is released. The hammering blocks repetitively hammers the protrusion blocks and axially returns back to the original position, thus configuring an impact output mode.