A vascular endothelial function inspection apparatus comprising: a first cuff (2, 2a, 2b) configured to be mounted to a first part of a subject; a cuff pressure control unit configured to control a pressure applied to the first cuff; a pressure sensor configured to be connected to the first cuff (2, 2a, 2b); a cuff pressure detection unit configured to detect a cuff pressure from an output of the pressure sensor; a pulse wave detection unit configured to detect pulse waves from the output of the pressure sensor; a blood pressure measuring unit configured to measure a blood pressure value based on the cuff pressure and the pulse waves; a storage unit that stores therein an elasticity index value (β) indicating an elasticity of a blood vessel of the subject; and an analysis unit configured to perform data processing for evaluating an endothelial function of the blood vessel, wherein the cuff pressure control unit is configured to apply a continuous pressure to the first part of the subject for a predetermined avascularization time period through the first cuff (2, 2a, 2b) mounted to the subject, wherein the blood pressure measuring unit is configured to calculate blood pressure values of the first part before and after the avascularization time period by using the output of the pressure sensor, and wherein the analysis unit is configured to calculate an index (α), which indicates a change in a blood vessel diameter, before (α 1) and after (α 2) the avascularization time period based on the elasticity Index value (β) and the blood pressure values measured before and after the avascularization time period, and to evaluate a vascular endothelial function of the subject by using the index before the avascularization time period and the index after the avascularization time period, wherein the elasticity index value (β) is calculated using the following equation: β = In Ps / Pd / D s − D d / Dd; Ps being a systolic blood pressure value, Pd being a diastolic blood pressure value, Ds being a maximum blood vessel diameter in systole, and Dd being a minimum blood vessel diameter in diastole. a first cuff (2, 2a, 2b) configured to be mounted to a first part of a subject; a cuff pressure control unit configured to control a pressure applied to the first cuff; a pressure sensor configured to be connected to the first cuff (2, 2a, 2b); a cuff pressure detection unit configured to detect a cuff pressure from an output of the pressure sensor; a pulse wave detection unit configured to detect pulse waves from the output of the pressure sensor; a blood pressure measuring unit configured to measure a blood pressure value based on the cuff pressure and the pulse waves; a storage unit that stores therein an elasticity index value (β) indicating an elasticity of a blood vessel of the subject; and an analysis unit configured to perform data processing for evaluating an endothelial function of the blood vessel, wherein the cuff pressure control unit is configured to apply a continuous pressure to the first part of the subject for a predetermined avascularization time period through the first cuff (2, 2a, 2b) mounted to the subject, wherein the blood pressure measuring unit is configured to calculate blood pressure values of the first part before and after the avascularization time period by using the output of the pressure sensor, and wherein the analysis unit is configured to calculate an index (α), which indicates a change in a blood vessel diameter, before (α 1) and after (α 2) the avascularization time period based on the elasticity Index value (β) and the blood pressure values measured before and after the avascularization time period, and to evaluate a vascular endothelial function of the subject by using the index before the avascularization time period and the index after the avascularization time period, wherein the elasticity index value (β) is calculated using the following equation: Ps being a systolic blood pressure value, Pd being a diastolic blood pressure value, Ds being a maximum blood vessel diameter in systole, and Dd being a minimum blood vessel diameter in diastole.