A sealing member 14 has a main seal 15 and a sub seal 21. The sub seal 21 is integrally formed with a first connecting element 20 that extends from the main seal 15. The first connecting element 20 has an upper bent portion 23a and a lower bent portion 23b. The sub seal 21 is at a higher position than the main seal 15 due to the upper and lower bent portions 23a, 23b. The first connecting element 20 has a rib 24 that extends along a longitudinal direction of the first connecting element 20. An upper thick portion 26a and a lower thick portion 26b are formed on the upper bent portion 23a and the lower bent portion 23b of the first connecting element 20, respectively. The rib 24 and the upper and lower thick portions 26a, 26b improve the rigidity of the first connecting element 20.