An automatic transmission apparatus (200) includes a transmission floor (210), at least one board (220), a first stopping unit (230), a second stopping unit (240), a plurality of inspecting units (250, 251, 252), and a controlling unit (260). The transmission floor has a plurality of rollers positioned at two long sides thereof. The at least one board is positioned on the rollers. The first and seccond stopping units are positioned along a path of movement of the at least one board along the transmission floor. The second stopping unit is along a predetermined distance from the first stopping unit. The inspecting units generate a plurality of inspecting signals according to a current position of the board. The controlling unit receives the inspecting signals and controls the first and second stopping units according to the inspecting signals. The first and second stopping units stop the at least one board from moving.