To improve the appearance of a building by integrally arranging a trunk part protruded down from a lid part with a seal part protruded from the trunk part, and setting the lid part and the part other than the lid part to different colors.

A joint seal member is formed of a lid part 40 on the upper end part, trunk parts 41A, 41B protruded down from the lid part 40, and seal parts 42 protruded sideways from the trunk parts 41A, 41B, which are integrally provided by use of rubber. The seal part 42 makes contact with each side end surface of a panel to seal the space between panels. The joint is blocked from above by the lid part 40, and it is set to, for example, gray by use of polyethylene chlorosulfonate. On the other hand, the trunk parts 41A, 41B and the seal parts 42 other than the lid part 40 are set to black by mixing carbon to chloroprene rubber. Thus, the color well-balanced with the surface of the panel which is formed of an extruded cement material can be provided, and the part other than the lid part 40 can be made excellent in mechanical property and physical property.