An illumination device for illuminating a main illumination space and a sub illumination space, said illumination device comprising: a main illumination member being configured to illuminate the main illumination space, a sub illumination member being configured to illuminate the sub illumination space, a scotopic luminance of the main illumination member being defined by a product obtained by multiplying a spectral distribution property of said main illumination member by a scotopic sensitivity of said main illumination member, a photopic luminance of the main illumination member being defined by a product obtained by multiplying the spectral distribution property of said main illumination member by a photopic sensitivity of said main illumination member, a scotopic luminance of the sub illumination member being defined by a product obtained by multiplying a spectral distribution property of said sub illumination member by a scotopic sensitivity of said sub illumination member, a photopic luminance of the sub illumination member being defined by a product obtained by multiplying the spectral distribution property of said sub illumination member by a photopic sensitivity of said sub illumination member, a ratio of the scotopic luminance of the main illumination member to the photopic luminance of the main illumination member being defined as an S/P ratio of the main illumination member, a ratio of the scotopic luminance of the sub illumination member to the photopic luminance of the sub illumination member being defined as an S/P ratio of the sub illumination member, wherein a color of light of said main illumination member and a color of light of said sub illumination member are set such that the S/P ratio of the sub illumination member is set to be greater than the S/P ratio of the main illumination member wherein said illumination device comprises a lamp fitting which is disposed above the space to be illuminated, characterized in that said lamp fitting being provided with an upper cover having an inner circumferential surface, which is a concave surface, said upper cover of said lamp fitting having a first arrangement surface and a second arrangement surface, said first arrangement surface having an upper inclination which extends to an upper direction as said first arrangement surface extends in a direction from the sub illumination space to the main illumination space, said second arrangement surface having an upper inclination which extends to an upper direction as said second arrangement surface extends in a direction from the main illumination space to the sub illumination space, said main illumination member being formed by the first arrangement surface and the light source on the first arrangement surface, said sub illumination member being formed by the second arrangement surface and the light source on the second arrangement surface. a main illumination member being configured to illuminate the main illumination space, a sub illumination member being configured to illuminate the sub illumination space, a scotopic luminance of the main illumination member being defined by a product obtained by multiplying a spectral distribution property of said main illumination member by a scotopic sensitivity of said main illumination member, a photopic luminance of the main illumination member being defined by a product obtained by multiplying the spectral distribution property of said main illumination member by a photopic sensitivity of said main illumination member, a scotopic luminance of the sub illumination member being defined by a product obtained by multiplying a spectral distribution property of said sub illumination member by a scotopic sensitivity of said sub illumination member, a photopic luminance of the sub illumination member being defined by a product obtained by multiplying the spectral distribution property of said sub illumination member by a photopic sensitivity of said sub illumination member, a ratio of the scotopic luminance of the main illumination member to the photopic luminance of the main illumination member being defined as an S/P ratio of the main illumination member, a ratio of the scotopic luminance of the sub illumination member to the photopic luminance of the sub illumination member being defined as an S/P ratio of the sub illumination member, wherein a color of light of said main illumination member and a color of light of said sub illumination member are set such that the S/P ratio of the sub illumination member is set to be greater than the S/P ratio of the main illumination member wherein said illumination device comprises a lamp fitting which is disposed above the space to be illuminated, characterized in that said lamp fitting being provided with an upper cover having an inner circumferential surface, which is a concave surface, said upper cover of said lamp fitting having a first arrangement surface and a second arrangement surface, said first arrangement surface having an upper inclination which extends to an upper direction as said first arrangement surface extends in a direction from the sub illumination space to the main illumination space, said second arrangement surface having an upper inclination which extends to an upper direction as said second arrangement surface extends in a direction from the main illumination space to the sub illumination space, said main illumination member being formed by the first arrangement surface and the light source on the first arrangement surface, said sub illumination member being formed by the second arrangement surface and the light source on the second arrangement surface.