A lighting device includes a pyroelectric sensor, a shutter and a lighting control unit. The lighting control unit is configured, when the lighting load is turned off, to turn the lighting load on if the pyroelectric sensor detects a change in infrared radiation. The lighting control unit is also configured, when the lighting load is turned on, to turn the lighting load off if a repetition count or time of a lighting retention time reaches a specified count or time, respectively, with no change in infrared radiation detected through the pyroelectric sensor within each lighting retention time per the passage of lighting retention time.