A multiband compatible antenna that resonates at a first frequency and a second frequency includes: a planar conductor including a feeding portion to which a signal is supplied, a grounding portion, and a slit between the feeding portion and grounding portion. The slit includes a first slit portion extending in a first direction and a second slit portion extending in a second direction intersecting the first direction from an end of the first slit portion. The first slit portion is disposed closer to one edge than a center of the planar conductor in the second direction, and the feeding portion is disposed to a side of the first slit portion closer to the one edge. The planar conductor includes a first element portion and a second frequency portion that resonate at the first frequency and the second frequency, respectively. The second slit portion is disposed in the first element portion.