To provide an antenna device in which a large number of operation bands can be attained easily while reducing the size and weight, and to provide a manufacturing method therefor, and a spacer for the antenna device.

The antenna device 1a includes a spacer 2 of three-dimensional structure having a plurality of side faces formed by folding a plate at a plurality of folding points 22. A plurality of planar antennas, having effective frequency bandwidths different from each other at least partially, are disposed, respectively, on the side faces different from each other.