Piezoelectric sensor and seat

A piezoelectric sensor includes: a piezoelectric element which is long and which includes a first electrode, a second electrode, and a piezoelectric body interposed between the first and second electrodes; and a laminate film which is long and which surrounds the piezoelectric element. The laminate film includes a wide portion whose length along a shorter side direction of the laminate film is not less than twice a length of the piezoelectric element which length is along a shorter side direction of the piezoelectric element.