A sealing device comprises a main body (1) provided with a partitionable space. The partitionable space is partitioned into a first partition space (16) and a second partition space (17) by the main body (1). The main body (1) is provided with a first body portion (10) and a second body portion (11). An outer side of the first body portion (10) is covered with a light shielding material (4), and/or the light shielding material (4) is sandwiched by the first body portion (10). An outer side of the second body portion (11) is covered with the light shielding material (4), and/or the light shielding material (4) is sandwiched by the second body portion (11). In the gap between the light shielding material (4) on the first body portion (10) and the light shielding material (4) on the second body portion (11), there is provided a shielding member (43) which at least shields one side of the gap and exceeds the length of the gap. By providing a separation material (42), the issue of easily photo-decomposable material to be shielded reacting with other materials contacted with and thus undergoing changes in physical and chemical properties is solved. By providing the shielding member (43) the stability of easily photo-decomposable materials can be ensured and excellent light shielding performance can be maintained. The sealing device of the present invention has application in the field of medical packaging materials.Linvention concerne un dispositif détanchéité comprenant un corps principal (1) pourvu dun espace à partitionnement. Lespace à partitionnement est partitionné en un premier espace à partitionnement (16) et un second espace à partitionnement (17) par le corps principal (1). Le corps principal (1) est pourvu dune première partie de corps (10) et dune seconde partie de corps (11). Un côté extérieur de la première partie de corps (10) est recouvert dun matériau de protection contre la lumière (4) et/ou le matériau de protection contre la lumière (4) est pris en san
