We performed combined therapy with trastuzumab-vinorelbine for 6 HER2 positive metastatic breast cancer patients from which informed consent was obtained. As the initial dosage, we administered 4 mg/kg of trastuzumab, followed by a dosage of 2 mg/kg every week thereafter. At the same time, 25 mg/m2 of vinorelbine was administered for 2 weeks, followed by a week of rest. Total administration frequency of trastuzumab was 13-34 times (median: 27 times) and vinorelbine was 8-22 times (median: 17 times). A partial response was seen in 4 patients and no change in 2, for a response rate of 66%. A fixed period effect was recognized in each case, and the TTP was 112-274 days (median: 205 days). The side effects recognized were leukopenia of grade 3 in 1 patient, but she recovered during a withdrawal period. After that, continuous administration was possible. Trastuzumab-vinorelbine combined therapy expanded treatment alternatives for HER2 positive metastatic breast cancer patients and might prolong life.