We report a 16-year-old woman patient with acute lymphoblastic leukemia (ALL) who developed severe critical illness polyneuropathy (CIP). She developed Bacillus cereus sepsis with multiple brain abscesses after chemotherapy. Although she was successfully treated and her general condition recovered, she could not stand. CIP was diagnosed based on the clinical course and electrophysiological studies. Since vincristine (VCR) was thought to have aggravated neurological symptoms, ALL treatment was continued without VCR. Five months from the onset of CIP, she could walk again with steppage gait. This case suggests that CIP can recover even while continuing ALL treatment, but omitting VCR.