A blood pressure measuring apparatus for measuring blood pressure of a subject using a cuff attached to the subject includes a processor and a memory to store instructions that are readable by the processor. As the instructions are executed by the processor, the apparatus generates a pulsation signal of the subject while increasing an inner pressure of the cuff; generates a first-order differential signal by differentiating the pulsation signal. The apparatus then detects an inappropriate attachment state of the cuff based on at least one of: a bottom value of the first-order differential signal; a relationship between a peak value and the bottom value of the first-order differential signal; an amplitude amount of the first-order differential signal including the bottom value in a unit time; and a relationship between the amplitude amount and an amplitude amount of the first-order differential signal including the peak value in a unit time.