An optical sheet includes a sheet-like body portion, and unit prisms arranged on one surface of the body portion. Each unit prism extends linearly in a direction intersecting the arrangement direction. Each unit prism, when viewed in a direction parallel to the arrangement direction of the unit prisms, has an uneven polygonal-line-shaped contour and, with reference to raised portions defined by the polygonal-line-shaped contour of each unit prism, the distance between a top of each raised portion, a farthest point from the body portion in the raised portion, and the body portion in the normal direction of the body portion is not constant. The optical sheet can prevent significant problems when it is superimposed on another member.