A vent structure includes: a first housing component having an opening portion for ventilation; a gas-permeable membrane that is attached to the first housing component to close the opening portion; and a laser welding portion that joins the first housing component with the gas-permeable membrane. The gas-permeable membrane includes a main body including a fluororesin film and a porous resin sheet that is laid on the main body. The porous resin sheet is located on the surface side of the vent structure. Both of the main body and the outer peripheral portion of the porous resin sheet that projects outwardly from the main body are fixed to the first housing component by the laser welding portion.