Fixing apparatus and film unit

A fixing apparatus comprising:

• a film that is tubular and configured to come into contact with a recording medium and rotate;
• a guide member disposed in an inside space of the film, elongated in a generatrix direction of the film, and configured to guide rotation of the film;
• a stay member disposed parallel to the generatrix direction of the film in the inside space of the film;
• a roller disposed so as to be in contact with an outside surface of the film;
• and
• a restriction structure disposed at a position between opposite ends of the film in the generatrix direction,
• wherein the stay member is configured to reinforce the guide member, the film and a roller forms a fixing nip portion between the film and the roller, and the recording medium, having a toner image formed on the recording medium, is heated to fix the toner image onto the recording medium at the fixing nip portion while the recording medium passes through the fixing nip portion, and
• wherein the restriction structure is configured to restrict movement of the guide member in a direction orthogonal to the generatrix direction of the film and also in a direction in which the stay member and the guide member are separated from each other.