Several biosimilars have appeared in cancer treatment. They should contribute to the reduction of medical cost. However, in Japan, a suspicion of medical staffs and patients to biosimilars and an obstruction of High-Cost Medical Expense Benefit to the burden reduction of patients suppress the use of biosimilars. Recently, several guidelines declare to promote the use of biosimilars. High-quality biosimilars are also going to be developed by next generation biotechnologies. The positive selection of biosimilars hopefully contribute to patients and national medical economy. In this review, we mention about the current subjects and future prospects of biosimilars.