A multi-beam reflectarray includes two or more element arrays including plural elements aligned along a predetermined direction. The multi-beam reflectarray is such that, in each of a first element group and a second element group included in at least one of the element arrays, a difference between phases of radio waves reflected by corresponding two elements is in proportion to a first product of a distance between the two elements and a value of a trigonometric function with respect to an angle of reflection by the two elements, and a distance between neighboring elements in the first element group is equal to a product of a rational number and a distance between neighboring elements in the second element group.