A base station apparatus provided with a function of performing communication using multiple beams implements appropriate beamforming while reducing interference power, thereby communication quality becomes stable and frequency efficiency or throughput is improved. The base station apparatus according to the present invention is a base station apparatus for communicating with a terminal apparatus, the base station apparatus including: a transmitter configured to transmit a synchronization signal block including a synchronization signal in a prescribed transmission window; and a controller configured to configure a size of the prescribed transmission window in which the synchronization signal block is transmitted, in which the transmitter notifies the terminal apparatus of information associated with QCL between two of the synchronization signal blocks transmitted in the prescribed transmission window.