A piezoelectric sensor includes: a lower substrate; a plurality of sensing transistors that are disposed on the lower substrate; a lower electrode that is disposed to cover the plurality of sensing transistors; a piezoelectric material layer that is disposed on the lower electrode; and an upper electrode that is disposed on the piezoelectric material layer. The piezoelectric material layer has a first thickness in a plurality of first areas in which the plurality of sensing transistors are disposed and has a second thickness which is greater than the first thickness in a second area in which the plurality of sensing transistors are not disposed. Accordingly, it is possible to further accurately and finely detect various types of biometric information.