A hardness testing instrument which measures a hardness of a specimen by pressing an indenter to a surface of the specimen, the hardness testing instrument comprising: a load applying section with the indenter or a flat indenter mounted thereon; a driving section configured to move the load applying section; a specimen table on which an object to be pressed by the indenter or the flat indenter is placed; a specimen table height adjustment section configured to adjust a height position of the specimen table; a control section configured to move, using the driving section, the load applying section from a reference position, to measure an indentation depth amount when the indenter is pressed with a predetermined load to a reference block having a predetermined hardness placed on the specimen table, an indentation depth amount storage section configured to store the indentation depth amount; the control section further being configured to move, using the driving section, the load applying section from the reference position, to measure the deformation amount of a load measuring instrument placed on the specimen table when the flat indenter is pressed with a predetermined load to the load measuring instrument, a deformation amount storage section configured to store the deformation amount; the hardness testing instrument being characterized by a height position obtaining section configured to obtain a height position of the specimen table according to the hardness of the reference block based on calculating difference between the deformation amount stored in the deformation amount storage section and the indentation depth amount stored in the indentation depth amount storage section; and a calibration section configured to calibrate the load by comparing a value of the load measured by the load measuring instrument and a value of the predetermined load when the flat indenter is pressed with the predetermined load to the load measuring instrument placed on the specimen table adjusted by the specimen table height adjustment section to the height position of the specimen table obtained by the height position obtaining section. a load applying section with the indenter or a flat indenter mounted thereon; a driving section configured to move the load applying section; a specimen table on which an object to be pressed by the indenter or the flat indenter is placed; a specimen table height adjustment section configured to adjust a height position of the specimen table; a control section configured to move, using the driving section, the load applying section from a reference position, to measure an indentation depth amount when the indenter is pressed with a predetermined load to a reference block having a predetermined hardness placed on the specimen table, an indentation depth amount storage section configured to store the indentation depth amount; the control section further being configured to move, using the driving section, the load applying section from the reference position, to measure the deformation amount of a load measuring instrument placed on the specimen table when the flat indenter is pressed with a predetermined load to the load measuring instrument, a deformation amount storage section configured to store the deformation amount; the hardness testing instrument being characterized by a height position obtaining section configured to obtain a height position of the specimen table according to the hardness of the reference block based on calculating difference between the deformation amount stored in the deformation amount storage section and the indentation depth amount stored in the indentation depth amount storage section; and a calibration section configured to calibrate the load by comparing a value of the load measured by the load measuring instrument and a value of the predetermined load when the flat indenter is pressed with the predetermined load to the load measuring instrument placed on the specimen table adjusted by the specimen table height adjustment section to the height position of the specimen table obtained by the height position obtaining section.