Bag for protecting head of automobile passenger, protecting device, and automobile

A bag for protecting a head of an automobile passenger, comprising:

• two sheets laminated together,
• a main path formed between the two sheets and having a gas inlet,
• a cushion formed between the two sheets and connected to the main path, said cushion including a top side to be arranged along a ceiling of the automobile, a bottom side, and chambers communicating with the main path to be expanded as a result of gas entering into the cushion from the main path, said chambers including an upper chamber extending along the top side in a direction of a line extending from the main path and having one end connected to the main path;
• a side chamber connected to the other end of the upper chamber and extending downwardly from the top side;
• a lower chamber extending along the bottom side of the bag and having one end connected to the side chamber;
• and an intermediate chamber communicating with and disposed between the lower chamber and the upper chamber, and separated from the side chamber, and
• first, second and third annular joining sections for partly joining the two sheets together inside the cushion to define the upper, side, lower and intermediate chambers and located at a corner between the upper and side chambers, a corner between the side and lower chambers and an end of the lower chamber away from the side chamber, respectively, each annular joining section having an annular shape.