The present invention provides a light-emitting element, a light-emitting device and an electronic device in which an optical path length through which generated light goes can be changed easily. The present invention provides a light-emitting element including a light-emitting layer between a first electrode and a second electrode, and a mixed layer in contact with the first electrode; in which the light-emitting layer includes a light-emitting substance; the mixed layer includes a hole transporting substance and a metal oxide showing an electron accepting property to the hole transporting substance, and has a thickness of 120 to 180 nm, and when a voltage is applied between the first electrode and the second electrode such that a potential of the first electrode is higher than that of the second electrode, the light-emitting substance emits light.