The present invention relates to a medium composition for production of botulinum toxin and, more particularly, to a medium composition for culture of Clostridium sp. capable of producing botulinum toxin. The medium composition of the present invention comprises a casein hydrolysate and at least one plant-derived peptone selected from the group consisting of a garden pea hydrolysate, a cotton seed hydrolysate and a wheat gluten hydrolysate. When the medium according to the present invention, which contains plant-derived peptones, casein hydrolysates and minerals, is used for culture of Clostridium botulinum, the growth rate of the bacterium in the medium is higher than that in each of the medium that is in current use and the medium comprising plant-derived peptones alone. In addition, when the medium of the present invention is used, a high concentration of botulinum toxin can be produced by culturing the bacterium in a safe manner.