An air-circulating mat for a seating device is disclosed. At a lower end part of a bag-shaped body, an opening portion for mounting an air blower is formed. A spacer ensures an air path through which the air flows inside the bag-shaped body and is contained in the bag-shaped body. This spacer is made of plastic and includes a plurality of convex parts and a plurality of flexible connection portions with flexibility for connecting the adjacent convex parts. At an upper end part on the right side of the bag-shaped body is an air circulating portion for discharging the air flowing through the air path to the outside. A battery containing portion for containing a battery that supplies electric power to the air blower is provided so as to continue to a predetermined end portion of the spacer located on a back portion side of a user in use.