A body-insertable apparatus includes an imaging unit that captures an in-vivo image of a subject; a signal processing unit that writes the in-vivo image in a memory, reads the in-vivo image from the memory on a pixel basis and converts the in-vivo image to serial information to transfer the serial information; and a rate converter that converts a transfer processing rate to a rate higher than a writing processing rate. The transfer processing rate is at which the signal processing unit reads the in-vivo image from the memory and converts the in-vivo image to the serial information to transfer the serial information. The writing processing rate is at which the signal processing unit writes the in-vivo image in the memory. The apparatus also includes a transmitting unit that wirelessly transmits the serial information transferred from the signal processing unit at a transmission rate corresponding to the transfer processing rate.