To improve sealability to an air passage by an inhalation valve element.

An inhaling valve element 20 is integrally projected in the horizontal direction on a pump chamber 35 side from an opening end 17b of a diaphragm part 17. On a peripheral edge part of an inhalation hole 32 closed by the inhaling valve element 20, a bulging part 33 for forcedly elastically deforming the inhaling valve element 20 toward the diaphragm part 17 is formed.