To provide a handy bubble generator obtaining a massage effect without needing a power source and jetting bubbles into hot water in a bathtub as if it were a jet.

A bubble generator for a bath agent includes a case body 1, and a bottom cover 10 with water holes 11. The body is formed with an inclined top wall 2, and the upper end of a partition piece 9 continuous with an inclined surface 7 faces, with a clearance, the inside of a round curve part at the distal end of the top wall. A plurality of bubble holes are formed in a horizontal part 4 continuous with the lower end of the round curve part, and the bottom cover is provided with a weight part 12. When the generator with a carbonic acid bath agent stored therein is arranged in a bathtub, bubbles of the bath agent generated reacting to hot water flowing in from the water holes in the bottom cover are energized through the inside of the body and released in a jet state into the bathtub from the bubble holes 5.