Biopsy devices (10, 10′) for acquiring tissue samples (59). In embodiments, exemplary biopsy devices include a cutter (127), a cannula (13) including a tissue-receiving cavity (42), a vacuum generating mechanism (17) and a tissue cutting mechanism (15). Vacuum generating mechanism draws tissue (47) into tissue-receiving cavity and tissue cutting mechanism cuts a tissue sample (59). Vacuum generating mechanism may provide positive air pressure for tissue sample ejection.