According to one embodiment, a sensor includes a structure body, a first flexible unit, and a first sensing unit. The structure body includes a first portion and a second portion. The second portion is linked to the first portion. The first portion is displaced along a first direction intersecting a direction connecting the first portion and the second portion. The second portion is displaced along a second direction according to the displacement of the first portion. The second direction intersects the first direction. The first flexible unit deforms along the second direction according to the displacement of the second portion along the second direction. The first sensing unit senses the deformation of the first flexible unit.