A hardness tester, comprising: an indentation former configured to provide a predetermined load to an indenter and further configured to press the indenter into a surface of a sample to form an indentation; and a measurer configured to detect a pressing depth of the indenter and a test force loaded on the indenter at the time of indentation formation to measure a pressing curve; characterized by further comprising: a definer configured to define, prior to beginning a measurement, an expected range for a value for one of a displacement, speed, and acceleration of the indenter during a process of approaching the sample; and a determiner configured to: - measure the value for one of the displacement, speed, and acceleration of the indenter during the process of approaching the sample, - perform detection of the surface of the sample as a zero point by applying a constant, predefined test force to the indenter such that the indenter approaches the sample at a constant speed, wherein at a point at which the value of displacement or the descent speed of the indenter changes by contacting the sample is detected as the zero point, and - when the measured value for one of the displacement, speed, and acceleration of the indenter during the process of approaching the sample is not within the expected range, determine that detection of the zero point has failed. an indentation former configured to provide a predetermined load to an indenter and further configured to press the indenter into a surface of a sample to form an indentation; and a measurer configured to detect a pressing depth of the indenter and a test force loaded on the indenter at the time of indentation formation to measure a pressing curve; characterized by further comprising: a definer configured to define, prior to beginning a measurement, an expected range for a value for one of a displacement, speed, and acceleration of the indenter during a process of approaching the sample; and a determiner configured to: - measure the value for one of the displacement, speed, and acceleration of the indenter during the process of approaching the sample, - perform detection of the surface of the sample as a zero point by applying a constant, predefined test force to the indenter such that the indenter approaches the sample at a constant speed, wherein at a point at which the value of displacement or the descent speed of the indenter changes by contacting the sample is detected as the zero point, and - when the measured value for one of the displacement, speed, and acceleration of the indenter during the process of approaching the sample is not within the expected range, determine that detection of the zero point has failed. a definer configured to define, prior to beginning a measurement, an expected range for a value for one of a displacement, speed, and acceleration of the indenter during a process of approaching the sample; and a determiner configured to: - measure the value for one of the displacement, speed, and acceleration of the indenter during the process of approaching the sample, - perform detection of the surface of the sample as a zero point by applying a constant, predefined test force to the indenter such that the indenter approaches the sample at a constant speed, wherein at a point at which the value of displacement or the descent speed of the indenter changes by contacting the sample is detected as the zero point, and - when the measured value for one of the displacement, speed, and acceleration of the indenter during the process of approaching the sample is not within the expected range, determine that detection of the zero point has failed. - measure the value for one of the displacement, speed, and acceleration of the indenter during the process of approaching the sample, - perform detection of the surface of the sample as a zero point by applying a constant, predefined test force to the indenter such that the indenter approaches the sample at a constant speed, wherein at a point at which the value of displacement or the descent speed of the indenter changes by contacting the sample is detected as the zero point, and - when the measured value for one of the displacement, speed, and acceleration of the indenter during the process of approaching the sample is not within the expected range, determine that detection of the zero point has failed.