A radio apparatus, a transmission control method and a transmission control program are provided in which both of adaptive array processing and adaptive modulation are supported and a transmission directivity control scheme can be selected according to a modulation scheme. The radio apparatus includes a modulation unit modulating transmission data based on a selected modulation scheme, a transmission scheme selection unit selecting one of a first transmission weight for forming transmission directivity to direct a beam of a transmission radio wave in a direction of a desired radio apparatus and direct a null of a transmission radio wave in a direction of an interference wave and a second transmission weight for forming transmission directivity to maximize reception power at a desired radio apparatus, a transmission weight generation unit generating the selected transmission weight, and a transmission weight processing unit generating array transmission data having transmission directivity based on the modulated transmission data and the generated transmission weight.