A pressure sensor includes a base substrate, a first insulating layer at the base substrate, a stationary electrode at the first insulating layer, a side-wall portion around the stationary electrode at the first insulating layer, and a membrane having electrical conductivity, facing the stationary electrode across a space, and supported by the side-wall portion. The side-wall portion includes a shield electrode on the first insulating layer and a second insulating layer on the shield electrode. A distance between the stationary electrode and the membrane is less than a distance between the shield electrode and the membrane.