In an array antenna apparatus, a first height of top faces of plurality of antenna elements is greater than or equal to a second height of a first top of a first electronic component relative to a first primary surface. The first electronic component is the tallest among one or more electronic components mounted on fourth primary surfaces of one or more first external circuit boards. A third height of a second primary surface is greater than a fourth height of fourth primary surfaces. Accordingly, the array antenna apparatus has good antenna characteristics.