A method of manufacturing a semiconductor light emitting element includes preparing a semiconductor stacked layer structure by stacking a first semiconductor layer and a second semiconductor layer in this order, forming a second electrode and an insulating layer in this order on the second semiconductor layer, exposing the first semiconductor layer by removing a part of the second semiconductor layer, forming a first electrode by forming a metal layer on the exposed first semiconductor layer and the insulating layer and flattening a surface of the metal layer, forming a first electrode-side bonding layer having a top layer made of Au on the first electrode, preparing a support substrate including a support substrate-side bonding layer having a top surface made of Au, and bonding the first electrode-side bonding layer and the support substrate-side bonding layer.