A force touch method of a touch input device comprising a touch input unit and a controller, the method comprises: a detecting step in which the controller detects a magnitude of a pressure of an object (h), which is input to the touch input unit; a first 3D touch function control step in which when the detected magnitude of the pressure increases from below a magnitude of a predetermined reference pressure to above the magnitude of the reference pressure, the controller controls such that the first predetermined 3D touch function is performed in the touch input device; and an N-th 3D touch function control step (S2250 to S2270) in which, while the object (h) is not released from the touch input unit, when the number for which the detected magnitude of the pressure increases from below the magnitude of the reference pressure to above the magnitude of the reference pressure is N, wherein N is a natural number greater than 1, the controller controls such that the N-th 3D touch function different from the first 3D touch function is performed in the touch input device, wherein, in the N-th 3D touch function control step (S2250 to S2270), when a number for which the detected magnitude of the pressure reduces to below the magnitude of an auxiliary reference force is at least one between a first time point (Ta), which is when the detected magnitude of the pressure increases from below the magnitude of the reference pressure to above the magnitude of the reference pressure, and a second time point (Tc), which is when the magnitude of the pressure, which is detected after the first time point (Ta), increases from below the magnitude of the reference pressure to above the magnitude of the reference pressure, the controller controls such that the 3D touch function set to be performed at the second time point (Tc) is performed in the touch input device characterized in that, when the magnitude of the pressure, which is detected between the first time point (Ta) and the second time point (Tc), does not reduce to below the magnitude of the auxiliary reference force, the 3D touch function set to be performed at the first time point (Ta) is also maintained at the second time point (Tc). a detecting step in which the controller detects a magnitude of a pressure of an object (h), which is input to the touch input unit; a first 3D touch function control step in which when the detected magnitude of the pressure increases from below a magnitude of a predetermined reference pressure to above the magnitude of the reference pressure, the controller controls such that the first predetermined 3D touch function is performed in the touch input device; and an N-th 3D touch function control step (S2250 to S2270) in which, while the object (h) is not released from the touch input unit, when the number for which the detected magnitude of the pressure increases from below the magnitude of the reference pressure to above the magnitude of the reference pressure is N, wherein N is a natural number greater than 1, the controller controls such that the N-th 3D touch function different from the first 3D touch function is performed in the touch input device, wherein, in the N-th 3D touch function control step (S2250 to S2270), when a number for which the detected magnitude of the pressure reduces to below the magnitude of an auxiliary reference force is at least one between a first time point (Ta), which is when the detected magnitude of the pressure increases from below the magnitude of the reference pressure to above the magnitude of the reference pressure, and a second time point (Tc), which is when the magnitude of the pressure, which is detected after the first time point (Ta), increases from below the magnitude of the reference pressure to above the magnitude of the reference pressure, the controller controls such that the 3D touch function set to be performed at the second time point (Tc) is performed in the touch input device characterized in that, when the magnitude of the pressure, which is detected between the first time point (Ta) and the second time point (Tc), does not reduce to below the magnitude of the auxiliary reference force, the 3D touch function set to be performed at the first time point (Ta) is also maintained at the second time point (Tc).