A stroller seat is mounted on a stroller and is provided with: a main part extending from a backrest to a seating part of the stroller and having a space therein through which air flows; an extension part protruding from at least one of the two side portions of the main body and having a space therein which communicates with the space of the main body; and a fan attachment part which is provided on the extension part and to which an electric fan can be attached. The main body has, on a surface to be in contact with a human body, an air discharge unit for discharging air therein to the outside. Air introduced by the electric fan attached to the fan attachment part flows into the main body through the extension part.