A shading device, comprising: a retractable and deployable shading curtain that includes at least one shading layer (241, 242) and has a first longitudinal side and a second longitudinal side opposite to the first longitudinal side; a drawing device configured to deploy the shading curtain; and a first guide rail having a groove configured to receive and guide the first longitudinal side of the shading curtain; wherein a deployed section of the first longitudinal side of the shading curtain is at least partially received in the groove when the shading curtain is in a partially deployed or finally deployed state; wherein the first longitudinal side has a support member (243, 244), by means of which the first longitudinal side is receivable and guidable in the groove; characterized in that the shading curtain includes a first shading layer made of a flexible material and a second shading layer made of a flexible material; wherein the first shading layer has a first support member, and the second shading layer has a second support member; wherein the first support member is configured to generate a magnetic attractive force with a first groove wall of the first guide rail, and the second support member is configured to generate a magnetic attractive force with a second groove wall of the first guide rail opposite to the first groove wall; and/or wherein the first support member is configured to generate a magnetic attractive force with a bottom of the first guide rail, and the second support member is configured to generate a magnetic attractive force with the bottom of the first guide rail. a retractable and deployable shading curtain that includes at least one shading layer (241, 242) and has a first longitudinal side and a second longitudinal side opposite to the first longitudinal side; a drawing device configured to deploy the shading curtain; and a first guide rail having a groove configured to receive and guide the first longitudinal side of the shading curtain; wherein a deployed section of the first longitudinal side of the shading curtain is at least partially received in the groove when the shading curtain is in a partially deployed or finally deployed state; wherein the first longitudinal side has a support member (243, 244), by means of which the first longitudinal side is receivable and guidable in the groove; characterized in that the shading curtain includes a first shading layer made of a flexible material and a second shading layer made of a flexible material; wherein the first shading layer has a first support member, and the second shading layer has a second support member; wherein the first support member is configured to generate a magnetic attractive force with a first groove wall of the first guide rail, and the second support member is configured to generate a magnetic attractive force with a second groove wall of the first guide rail opposite to the first groove wall; and/or wherein the first support member is configured to generate a magnetic attractive force with a bottom of the first guide rail, and the second support member is configured to generate a magnetic attractive force with the bottom of the first guide rail.