The utility model discloses an automatic catalyst feeder, which aims at solving a problem that catalyst tends to accumulate at the bottom of an internal weighing barrel equipped in the present automatic catalyst feeder. The automatic catalyst feeder is provided with a fluidization tank (1), and an internal weighing barrel (3) is arranged inside the fluidization tank (1). An annular bearing board (4), a collecting plate (5) shaped like an inverted circular table board, and a fluidization air distributor are arranged at the bottom of a cylindrical barrel (31) of the internal weighing barrel (3). The edge of the top of the collecting plate (5) is connected with the edge of a central hole of the annular bearing board (4). The fluidization air distributor is arranged at the hole at the bottom of the collecting plate (5) to cover the hole. The included angle of the collecting plate (5) and the horizontal plane is larger than an accumulation angel of catalyst. The automatic catalyst feeder can be used for providing catalyst or auxiliary agent for FCC (fluid catalytic cracking) devices and the like periodically and quantificationally.