Provided is a control method for a negative pressure pump for a motor which can stabilize, accurately and efficiently control the negative pressure pump. The present invention relates to a method of controlling a negative pressure pump (4) for generating a negative pressure in a vacuum booster (2) of an automobile. The control method of the negative pressure pump (4) includes a mode switching step of switching between a low ground control mode and a high ground control mode, wherein the low control mode is a control mode for controlling the negative pressure pump (4) when the vehicle is in a low land, The control mode is a control mode in which the negative pressure pump (4) is controlled in a manner different from the low control mode when the vehicle is located at a height above the altitude of the vehicle. In the mode switching step, the first atmospheric pressure thresholds (b1) and The second atmospheric pressure threshold value (b2) is set to a different value, the first atmospheric pressure threshold value is a value of the atmospheric pressure when the control mode is switched from the low control mode to the high ground control mode, and the second atmospheric pressure threshold is switched from the high ground control mode to the low control Mode when the value of atmospheric pressure.