There are provided a planar antenna that reduces interactions between an antenna section and a peripheral circuit section on each other's electric operations in an apparatus in which an antenna and a peripheral circuit are arranged together on a printed circuit board, and a communication device and a card-type terminal that use the planar antenna. The planar antenna has the antenna section and the peripheral circuit section which are arranged on the printed circuit board. The planar antenna includes: on one surface of the printed circuit board, a plate element that constitutes the antenna section, a microstrip line that is connected with the plate element and feeds electricity from a peripheral circuit to the plate element, and a peripheral circuit mounting area in which the peripheral circuit section is arranged; and, on the other surface of the printed circuit board, a first ground portion that constitutes a ground-side conductor of the peripheral circuit section, and a second ground portion that constitutes a ground-side conductor of the microstrip line. The second ground portion is arranged on the printed circuit board other than the first ground portion. The connection between the plate element and the microstrip line is located on the side of the second ground portion away from the first ground portion.