A multi-antenna device includes a grounding plate, a first antenna and a second antenna. The first antenna includes a first feed element that is grounded to the grounding plate via a first feed point. The second antenna includes a second feed element that is grounded to the grounding plate via a second feed point. The first feed point and the second feed point are disposed such that a straight line connecting the first feed point and a center of the grounding plate and a straight line connecting the second feed point and the center of the grounding plate are substantially perpendicular to each other in a plan view.