Artificial illumination device for generating natural light similar to that from the sun and the sky with making an observer experience a visual infinite depth perception of a sky and sun image when an observer directly looks at said artificial illumination device, comprising: a direct-light source comprising a first emitting surface and configured to produce, from a primary light, a direct light that exits the first emitting surface into a direct-light direction at low divergence, the direct-light source comprising a plurality of pairs of a first light-emitting device (14; 60) positioned upstream the first emitting surface and configured to emit the primary light and a collimator (16; 64) configured to collimate the primary light emitted by the first light-emitting device along the direct-light direction; and a diffused-light generator configured to cause diffused light (35; 242) at a second emitting surface, wherein one of the first emitting surface and the second emitting surface is positioned downstream with respect to the other and forms an outer emitting surface of the artificial illumination device or both the first emitting surface and the second emitting surface coincide to form the outer emitting surface of the artificial illumination device, wherein the artificial illumination device is configured such that the direct-light source and the diffused-light generator co-operate to form outer light at the outer emitting surface which comprises a first light component which propagates within a low divergence cone along the direct light direction and a second light component which propagates along directions outside the low divergence cone wherein the first light component has a correlated color temperature which is lower than a CCT of the second light component so that an observer sees, when looking towards the first emitting surface, a bright spot surrounded by a bluish background which mimics the sky, the bright spot having lower CCT, corresponding to the sun and moving, when the observer moves relatively to the first emitting surface as if the bright spot stemmed from an object positioned at infinity. a direct-light source comprising a first emitting surface and configured to produce, from a primary light, a direct light that exits the first emitting surface into a direct-light direction at low divergence, the direct-light source comprising a plurality of pairs of a first light-emitting device (14; 60) positioned upstream the first emitting surface and configured to emit the primary light and a collimator (16; 64) configured to collimate the primary light emitted by the first light-emitting device along the direct-light direction; and a diffused-light generator configured to cause diffused light (35; 242) at a second emitting surface, wherein one of the first emitting surface and the second emitting surface is positioned downstream with respect to the other and forms an outer emitting surface of the artificial illumination device or both the first emitting surface and the second emitting surface coincide to form the outer emitting surface of the artificial illumination device, wherein the artificial illumination device is configured such that the direct-light source and the diffused-light generator co-operate to form outer light at the outer emitting surface which comprises a first light component which propagates within a low divergence cone along the direct light direction and a second light component which propagates along directions outside the low divergence cone wherein the first light component has a correlated color temperature which is lower than a CCT of the second light component so that an observer sees, when looking towards the first emitting surface, a bright spot surrounded by a bluish background which mimics the sky, the bright spot having lower CCT, corresponding to the sun and moving, when the observer moves relatively to the first emitting surface as if the bright spot stemmed from an object positioned at infinity.