In a luminescence device formed of one or plural layers of organic film between a cathode and an anode, at least one layer is a luminescence layer, and a luminescence molecule of a metal coordination compound having a basic structure represented by formula (1) ML.sub.mL'.sub.n and having a substituent on at least one of cyclic groups incorporated as a guest in a host material at a concentration of at least 8 wt. %, which is higher than a concentration at which a luminescence molecule of a similar structure but having no substituent exhibits a maximum luminescence efficiency to form the luminescence layer. As a result, a high-efficiency luminescence device is provided, which is less likely to cause concentration extinction even when a luminescence molecule is contained at a high concentration relative to the host material in the luminescence layer.