Disclosed is a coordinate input device, having a vibration transmission plate, that simplifies the measurement of a vibration transmission speed, which is used as a known constant to calculate a distance between a vibration input location and individual vibration sensors, and that ensures the accurate performance of calculations to acquire input coordinates. According to the present invention, a vibration transmission plate has anisotropic properties that are associated with two axes. As a result, the speeds at which vibrations arrive at vibration sensors differ depending on which pair of vibration sensors, 6a and 6d, or tb and 6c, is involved. Therefore, the vibration transmission speeds are measured for the individual pairs of vibration sensors, 6a and 6d, and 6b and 6c, and the measured values are stored as known values. These values are employed as constants to be used for calculations performed to acquire coordinates.