A package has a first electrode, a second electrode, and a first resin body. The first resin body has a retainer portion and a wall portion. The retainer portion retains the first electrode and the second electrode and forms a bottom portion of the package together with the first electrode and the second electrode. The wall portion surrounds a mounting region on the bottom portion and has a pair of opposite outer sides. Each of the first electrode and the second electrode has an outer lead portion extending outwardly from respective one of the pair of opposite outer sides of the wall portion. The first resin body further has a flange portion having parts extending from the pair of opposite outer sides of the wall portion. Each of the outer lead portions extends outwardly beyond a distal end of the corresponding part of the flange portion in plan view.