A vacuum processing apparatus includes a transfer chamber filled with a gas to have an upper limit of a target pressure range, a gas supply system connected to a gas supply source to supply the gas into the transfer chamber, a gas exhaust system for releasing the gas from within the transfer chamber, first and second vacuum chambers connected to the transfer chamber, first and second gate valves interposed between the transfer chamber and the vacuum chambers, which selectively permit the transfer chamber and the vacuum chambers to communicate with each other and a transfer mechanism for transferring a target object from the first vacuum chamber to the transfer chamber via the first gate valve and for transferring the target object from the transfer chamber to the second vacuum chamber via the second gate valve. An opening/closing valve is provided in the gas supply system for selectively supplying the gas from the gas supply source into the transfer chamber, a gas loading space being defined upstream of the opening/closing valve to permit the gas having a volume and pressure set in accordance with the upper limit of a target pressure range to be stored in the gas loading space when the opening/closing valve is closed.