A gel sealing device includes a gel sealing block (5) which provides a sealing section (22) through which the elongate parts (13, 14) extend. The gel sealing block (5) includes an upper flange (11) and a lower flange (12) with a support section (11a, 12a, 12b) disposed therebetween. The upper and lower flanges (11, 12) sandwiches, in direction of extension of the elongate parts (13, 14), a gel inner ring (7) supported by said support section (2) and a gel outer ring (6, 10a) covering the gel inner ring (7) in a radial direction extending transverse to said extension direction. The gel inner ring (7) and the gel outer ring (6, 10a) are made of a gel sealing material.