In a first scanning lens, a first lens section and a second lens section are vertically overlapped in such a manner as to separate lens centers thereof by a first distance. In a second scanning lens, a third lens section and a fourth lens section are vertically overlapped in such a manner as to separate lens centers thereof by a second distance equal to the first distance. A vertical positional relationship of the first lens section with the second lens section is the same as a vertical positional relationship of the third lens section with the fourth lens section. Further, a separating direction of a lens center of the first lens section from that of the second lens section is opposite to a separating direction of a lens center of the third lens section from that of the fourth lens section.