An apparatus for measuring a depth of a three-dimensional (3D) object includes a control unit generating the 3D object by adjusting parameters of a 3D pattern. A 3D display unit displays the 3D object with a preset depth. An input unit generates an input signal based on an input received from a user. A rail extends in a front and a rear of the 3D display unit. A moving body is movable on the rail. Movement of the moving body is adjusted based on the input signal. A distance sensor measures a distance to the moving body.