To comfortably use an air mat as a bed by providing multiple bulkheads, injecting air, matching the lower face of the air mat wit the irregular shape of seats, and forming the upper face into a flat face.

Multiple partitions made of a synthetic resin sheet are connected to the upper face 1 and lower face 2 of an air mat by thermal fusion in the air mat. When air is injected into the air mat from an injection port, air is filled in all bags through the vent holes of the partition, and the bags are uniformly pushed from the inside by the air pressure. One side of each partition is matched with the cross sectional shape of each seat 7 when it is horizontally prostrated, and the other opposite side is made a straight line. One side of each partition keeps the lower face 2 of the air mat in the shape matched with the irregularities of the seat 7, and the other opposite side is made a straight line, thus a flat face is formed on the upper face 1 of the air mat. The air mat spread on the seats 7 of passenger car prostrated horizontally into a fully flat face can be used as a comfortable and simplified bed made flat on the upper face regardless of the irregularities of the seats of the passenger car.