This invention provides a blood pressure measuring apparatus capable of deriving an appropriate pressure value even in an environment in which the environmental temperature constantly changes. A blood pressure measuring apparatus has a cuff to be attached to the external ear and its periphery, a signal acquiring unit which acquires a pulse wave signal and/or Korotkoff sounds from a pressed portion and its periphery pressed by the cuff, a pressure sensor which outputs a predetermined signal level corresponding to a pressure value in the cuff, a temperature measuring unit which measures a temperature near the pressure sensor, a blood pressure value deriving unit which derives a blood pressure value on the basis of a pressure value derived from the signal level, and the pulse wave signal and/or the Korotkoff sounds, and an adjusting unit which performs adjustment which compensates for a characteristic change of the pressure sensor with respect to the pressure value, if the temperature measured by the temperature measuring unit changes by a predetermined value or more.