Ventilation device, ventilation unit, and power conversion device

A ventilation device comprising:

• a housing;
• a shutter case attached to the housing and having an opening;
• a fan configured to perform one of air blowing outside air into the housing through the opening, and exhausting air inside the housing to outside through the opening;
• and
• a shutter that is rotatably provided in the shutter case, the shutter partitioning inside of the shutter case into a first chamber communicated with the opening and a second chamber different from the first chamber, the shutter being configured to open and close the opening by a rotation operation,
• wherein the fan is disposed in one of a first chamber side of the shutter case in the housing and the first chamber of the shutter case,
• the first chamber is a first region that is one of a positive pressure region and a negative pressure region of the fan,
• the second chamber is a second region that is the other of the positive pressure region and the negative pressure region of the fan,
• the second chamber of the shutter case communicates only with a region same as the second region in the housing, and
• the shutter is provided such that a pressure received from the second chamber is smaller than a pressure received from the first chamber.