Providing a three-dimensional surveying device and method capable of stably acquiring three-dimensional data with high accuracy. The device includes a mobile body, a measurement target, a collimation distance measuring unit fixed to the mobile body, a scanner unit, and a control computation section. The scanner unit is provided integrally and rotatably with respect to the collimation distance measuring unit. The control computation section is configured to calculate a coordinate value of a measurement center of the collimation distance measuring unit based on a distance measured by the collimation distance measuring unit, a first horizontal and first vertical angle, and to calculate a coordinate value of a measurement target object based on the coordinate value of the measurement center, an external orientation element of the scanner unit with respect to the collimation distance measuring unit, a distance measured by the scanner unit and a second horizontal and second vertical angle.