To provide a joint filler for a bathtub, capable of securely sealing the gap between the bathtub and a wall surface or between a counter adjacent to the bathtub and the wall surface.

The joint filler 20 made of an elastic material is attached to the gap between the bathtub 14 and the wall surface 11, etc. and between the counter 16 and a right wall surface panel 15b. The joint filler 20 consists of a front surface sealing part 21 disposed along the front surface side of the bathtub 14, and an insertion pressure-contact part 22 disposed along a side surface of the bathtub 14 to extend from the rear surface of the front surface sealing part 21 toward the inner side of the gap. The insertion pressure-contact part 22 is curved so that the center side of the insertion pressure-contact part 22 in the vertical direction is energized toward the side surface of the bathtub 14. In addition, elastic fin parts 23 and 24 are formed in a projecting part of the insertion pressure-contact part 22. The surface sealing part 21 consists of a bathtub close contact part 21a close to the bathtub 14 and a wall surface close contact part 21b close to the wall surface 11.