A probe apparatus of inspecting an electrical characteristic of a power device that is formed on a semiconductor wafer and has electrodes on front and rear surfaces thereof, the probe apparatus comprising: a movable mounting table configured to mount and support the semiconductor wafer thereon; a probe card that is provided above the mounting table to face the mounting table, and is configured to support a probe needle (24G, 24S) having a leading end to be come into contact with the electrode on the front surface of the power device, the electrode on the front surface of the power device being exposed at a front surface of the semiconductor wafer supported on the mounting table; a first connection conductor (26G, 26S) configured to connect the probe needle (24G, 24S) and a corresponding first terminal of a tester; a mounting surface conductor that serves as a mounting surface of the mounting table and is configured to be in contact with the electrode on the rear surface of the power device, the electrode on the rear surface of the power device being exposed at a rear surface of the semiconductor wafer supported on the mounting table; a contactor that is provided at the mounting table and is configured to be vertically moved and electrically connected with the mounting surface conductor; a contact plate, having a conductivity, provided between the mounting table and the probe card to come into contact with the contactor at a bottom surface thereof and configured to surround the probe needle (24G, 24S); a second connection conductor configured to connect the contact plate and a corresponding second terminal of the tester; and a gas supply device configured to supply a gas to the vicinity of the probe needle (24G, 24S) through an inside or a vicinity of the contact plate in order to form an atmosphere of a pressure higher than an atmospheric pressure in the vicinity of the probe needle (24G, 24S) when inspecting the electrical characteristic of the power device, characterized in that by moving the contactor upward, an upper end of the contactor is bought into contact with a bottom surface of the contact plate, and an electric conduction is achieved via the mounting surface conductor, the contactor and the contact plate. a movable mounting table configured to mount and support the semiconductor wafer thereon; a probe card that is provided above the mounting table to face the mounting table, and is configured to support a probe needle (24G, 24S) having a leading end to be come into contact with the electrode on the front surface of the power device, the electrode on the front surface of the power device being exposed at a front surface of the semiconductor wafer supported on the mounting table; a first connection conductor (26G, 26S) configured to connect the probe needle (24G, 24S) and a corresponding first terminal of a tester; a mounting surface conductor that serves as a mounting surface of the mounting table and is configured to be in contact with the electrode on the rear surface of the power device, the electrode on the rear surface of the power device being exposed at a rear surface of the semiconductor wafer supported on the mounting table; a contactor that is provided at the mounting table and is configured to be vertically moved and electrically connected with the mounting surface conductor; a contact plate, having a conductivity, provided between the mounting table and the probe card to come into contact with the contactor at a bottom surface thereof and configured to surround the probe needle (24G, 24S); a second connection conductor configured to connect the contact plate and a corresponding second terminal of the tester; and a gas supply device configured to supply a gas to the vicinity of the probe needle (24G, 24S) through an inside or a vicinity of the contact plate in order to form an atmosphere of a pressure higher than an atmospheric pressure in the vicinity of the probe needle (24G, 24S) when inspecting the electrical characteristic of the power device,