Glococardiocidin a derivative or its salt, as shown in formula (I), the preparation method thereof, and the use in the preparation of drugs for treating autoimmune diseases and tumors which are intractable diseases such as erythematodes, psoriasis and triple negative breast cancer. 1)式(I)に示されるグローコカリキシンA誘導体又はその塩、その調製方法、及び、エリマトーデス、乾癬やトリプルネガティブ乳癌等の難病とされる自己免疫疾患や腫瘍を治療する薬物の調製における用途。 【化1】【選択図】図1