A base station device includes: an acquisition unit that acquires reception quality of each of a plurality of carriers from a terminal device that performs primary cell connection for transmission and reception of a control channel signal using a carrier whose reception quality is most preferable; a decision unit that decides an amount of increase in transmission power of one of the carriers based on the reception quality acquired by the acquisition unit; a determination unit that estimates whether switching of the primary cell connection occurs in case of increasing the transmission power by the amount of increase and determines whether to increase the transmission power according to the estimation result; and an instruction unit that instructs a transmission unit to increase the transmission power of the carrier by the amount of increase when the determination unit determines to increase the transmission power.