A liquid crystal optical device (110, 111, 112, 113, 114, 130, 140, 141), comprising: a first substrate unit including a first substrate having a first surface and a first side, the first side extending in a first side direction when projected onto a plane parallel to the first surface, the first substrate being light-transmissive, and a plurality of band-shaped first electrodes extending in parallel to each other on the first surface in a first direction and being separated from each other in a direction orthogonal to the first direction; a second substrate unit including a second substrate having a second surface opposing the first surface, the second substrate being light-transmissive, and a plurality of band-shaped second electrodes extending in parallel to each other on the second surface in a second direction and being separated from each other in a direction orthogonal to the second direction; and a liquid crystal layer including liquid crystal molecules provided between the first substrate unit and the second substrate unit, characterised by a first angle (θ1) in a first rotation direction from the first side direction to the first direction being less than 90 degrees and more than 0 degrees, a second angle (θ2) in the first rotation direction from the first side direction to the direction of the second direction when projected onto the plane being different from the first angle (θ1), less than 90 degrees, and more than 0 degrees, a third angle (θ3) in the first rotation direction from the first side direction to the direction of the long-axis direction (31 a) of the liquid crystal molecules when projected onto the plane being different from the first angle (θ1) and different from the second angle (θ2), wherein said long-axis direction (31 a) of the liquid crystal molecules is either associated with an activated state of the liquid crystal layer in which a voltage larger than a threshold voltage is applied to the liquid crystal layer, or with a non-activated state of the liquid crystal layer in which no voltage or a voltage not more than the threshold voltage is applied to the liquid crystal layer. a first substrate unit including a first substrate having a first surface and a first side, the first side extending in a first side direction when projected onto a plane parallel to the first surface, the first substrate being light-transmissive, and a plurality of band-shaped first electrodes extending in parallel to each other on the first surface in a first direction and being separated from each other in a direction orthogonal to the first direction; a second substrate unit including a second substrate having a second surface opposing the first surface, the second substrate being light-transmissive, and a plurality of band-shaped second electrodes extending in parallel to each other on the second surface in a second direction and being separated from each other in a direction orthogonal to the second direction; and a liquid crystal layer including liquid crystal molecules provided between the first substrate unit and the second substrate unit, characterised by a first angle (θ1) in a first rotation direction from the first side direction to the first direction being less than 90 degrees and more than 0 degrees, a second angle (θ2) in the first rotation direction from the first side direction to the direction of the second direction when projected onto the plane being different from the first angle (θ1), less than 90 degrees, and more than 0 degrees, a third angle (θ3) in the first rotation direction from the first side direction to the direction of the long-axis direction (31 a) of the liquid crystal molecules when projected onto the plane being different from the first angle (θ1) and different from the second angle (θ2), wherein said long-axis direction (31 a) of the liquid crystal molecules is either associated with an activated state of the liquid crystal layer in which a voltage larger than a threshold voltage is applied to the liquid crystal layer, or with a non-activated state of the liquid crystal layer in which no voltage or a voltage not more than the threshold voltage is applied to the liquid crystal layer.