A composite molded article comprising: a main body portion including, a bottom wall portion formed of an elastically deformable polymer material, and a peripheral wall portion protruding so as to surround a peripheral edge of the bottom wall portion and formed of an elastically deformable polymer material; a vent hole passing through the bottom wall portion; and a gas permeable membrane integrally connected to the main body portion and is permeable to gas but is impermeable to liquid, wherein the gas permeable membrane is arranged to the bottom wall portion so as to cover the vent hole and connected to the bottom wall portion at a periphery of the vent hole, and wherein the bottom wall portion includes at least one rigid body portion which is more difficult to be deformed than the bottom wall portion at an outer peripheral part of the gas permeable membrane.