Disclosed is a coordinate input apparatus including a vibrating input pen 3, a piezoelectric element 4 in the pen 3, a vibration transfer plate 8 and vibration sensors 6 provided around the vibration transfer plate 8. The vibrator 4 is driven by a vibrator driving circuit 2 to generate a vibration, which is transmitted to vibration transfer plate 8. The apparatus is capable of calculating coordinate thereon accurately with phase information of detected signal waveform.