QUANTUM CASCADE LASER ELEMENT AND QUANTUM CASCADE LASER DEVICE

A quantum cascade laser element includes: a semiconductor substrate; a semiconductor laminate formed on the semiconductor substrate to include an active layer having a quantum cascade structure and to have a first end surface and a second end surface facing each other in a light waveguide direction; a first electrode; a second electrode; an insulating film continuously formed from the second end surface to a region on a second end surface side of at least one surface of a surface on an opposite side of the first electrode from the semiconductor laminate and a surface on an opposite side of the second electrode from the semiconductor substrate; and a metal film formed on the insulating film to cover at least the active layer when viewed in the light waveguide direction. An outer edge of the metal film does not reach the one surface when viewed in the light waveguide direction.