A brake system (5, 5A, 5B) comprising: an electromagnetic brake device configured to apply a brake to a rotary shaft when current is not applied to the brake system and release the brake on the rotary shaft when current is applied to the brake system; and a brake release device (7, 30) configured to forcibly release the brake on the rotary shaft when current is not applied to the brake system, characterized in that the electromagnetic brake device includes: a brake disc integrated with the rotary shaft; a stator disposed facing the brake disc; a brake plate positioned opposite to the stator with respect to the brake disc; an armature disposed between the brake disc and the stator and cooperating with the brake plate to hold the brake disc between the armature and the brake plate; an urging member disposed between the stator and the armature and configured to urge the armature such that the armature is pressed against the brake disc; and a magnet coil disposed in the stator and configured to be excited when current is applied to the magnet coil, and the brake release device (7, 30) includes: a guide member having a tube shape; a release plate disposed within the guide member and engaged with the armature; and a transfer unit (26, 32) that is configured to move the release plate in a direction in which the rotary shaft extends, characterised in that - the transfer unit is disposed within the guide member, and includes a bag that is configured to expand and contract in the direction in which the rotary shaft extends and an air supplier that is configured to supply air into the bag; or - the transfer unit (32, 32A) includes a hydraulic pressure source (35, 40) that supplies hydraulic oil into a space defined by the guide member and the release plate, and a valve that is configured to discharge the hydraulic oil from the space. an electromagnetic brake device configured to apply a brake to a rotary shaft when current is not applied to the brake system and release the brake on the rotary shaft when current is applied to the brake system; and a brake release device (7, 30) configured to forcibly release the brake on the rotary shaft when current is not applied to the brake system, characterized in that the electromagnetic brake device includes: a brake disc integrated with the rotary shaft; a stator disposed facing the brake disc; a brake plate positioned opposite to the stator with respect to the brake disc; an armature disposed between the brake disc and the stator and cooperating with the brake plate to hold the brake disc between the armature and the brake plate; an urging member disposed between the stator and the armature and configured to urge the armature such that the armature is pressed against the brake disc; and a magnet coil disposed in the stator and configured to be excited when current is applied to the magnet coil, and a brake disc integrated with the rotary shaft; a stator disposed facing the brake disc; a brake plate positioned opposite to the stator with respect to the brake disc; an armature disposed between the brake disc and the stator and cooperating with the brake plate to hold the brake disc between the armature and the brake plate; an urging member disposed between the stator and the armature and configured to urge the armature such that the armature is pressed against the brake disc; and a magnet coil disposed in the stator and configured to be excited when current is applied to the magnet coil, and the brake release device (7, 30) includes: a guide member having a tube shape; a release plate disposed within the guide member and engaged with the armature; and a transfer unit (26, 32) that is configured to move the release plate in a direction in which the rotary shaft extends, characterised in that - the transfer unit is disposed within the guide member, and includes a bag that is configured to expand and contract in the direction in which the rotary shaft extends and an air supplier that is configured to supply air into the bag; or - the transfer unit (32, 32A) includes a hydraulic pressure source (35, 40) that supplies hydraulic oil into a space defined by the guide member and the release plate, and a valve that is configured to discharge the hydraulic oil from the space. a guide member having a tube shape; a release plate disposed within the guide member and engaged with the armature; and a transfer unit (26, 32) that is configured to move the release plate in a direction in which the rotary shaft extends, characterised in that - the transfer unit is disposed within the guide member, and includes a bag that is configured to expand and contract in the direction in which the rotary shaft extends and an air supplier that is configured to supply air into the bag; or - the transfer unit (32, 32A) includes a hydraulic pressure source (35, 40) that supplies hydraulic oil into a space defined by the guide member and the release plate, and a valve that is configured to discharge the hydraulic oil from the space. - the transfer unit is disposed within the guide member, and includes a bag that is configured to expand and contract in the direction in which the rotary shaft extends and an air supplier that is configured to supply air into the bag; or - the transfer unit (32, 32A) includes a hydraulic pressure source (35, 40) that supplies hydraulic oil into a space defined by the guide member and the release plate, and a valve that is configured to discharge the hydraulic oil from the space.