To provide an apron structure by which slide in a vertical direction can be smoothly done without being influenced by the warp of the upper half of an apron.

The apron structure has a vertical slide mechanism in which the upper half of an apron divided in a vertical direction is secured to the inner side of a flange of a bathtub, the lower half is secured slidably in a vertical direction along a fitting secured to a bathtub wall face in the lateral side of the bathtub, and a falling preventing means supporting the lower apron having slid upward is secured to the wall face.