Excimer lamp

An excimer lamp comprising:

• a tubular housing portion made of a light-transmitting material, extending along a predetermined axis, and having a sealed internal space;
• an internal electrode held on one end side of the housing portion and accommodated in the internal space;
• and
• a discharge gas with which the internal space is filled, wherein
• one end side of the internal electrode is electrically connected to a power supply member provided with a metal foil electrically connected to the internal electrode and is sealed together with the power supply member to one end side of the housing portion via a sealing portion,
• the other end side of the internal electrode protrudes into the internal space, and
• a protrusion length, being a length of the internal electrode in the internal space and a length from one end of the internal space to the other end of the internal electrode, is equal to or less than a length from the other end of the internal electrode to the other end of the internal space in a direction along the axis.