In an optical unit, a first swing mechanism swings a holder with reference to the y-axis direction, and a second swing mechanism swings the holder with reference to the z-axis direction. A case has a first recess that accommodates at least a part of a first protrusion of the holder and a second recess that accommodates at least a part of a second protrusion of the holder. The first recess has a first side surface located on one side in the y-axis direction of the first protrusion, a second side surface located on the other side in the y-axis direction of the first protrusion, and a bottom surface. The second recess has a first side surface located on one side in the y-axis direction of the second protrusion, a second side surface located on the other side in the y-axis direction of the second protrusion, and a bottom surface.