An antenna unit (4a to 4h 24a 34a 44a) includes a receiving antenna (11 31) which receives in-vivo information of a subject (1) transmitted from a capsule medical apparatus (2), a wireless-signal generator (13 43) which receives the in-vivo information of the subject (1) received by the receiving antenna (11 31) and generates a wireless signal including the received in-vivo information, a power supply unit (14 25) which supplies power for the wireless signal generator (13 43), an outer covering (10 25b) on which the receiving antenna (11 31), the wireless-signal generator (13 43), the transmitting antenna (12), and the power supply unit (14 25) are mounted. The power supply unit (14 25) is flexible and can be transformed easily according to transformation of the outer covering (10 25b).
