To provide a simple shading system for a vehicle without a need of mounting a measuring instrument.

In Japan, an angle of elevation of the sun on winter solstice is smallest, and the angle of elevation of the sun is 8.5 degrees on 8 o'clock in the morning and on 4 o'clock in the afternoon at 35 degrees of north latitude. A position of a seat 110 can be detected by output signals of individual sensors 116-118. A position of an eye toward the seat 110 can be found by dimension of an occupant, for example, height of the occupant based on statics. This can determine the position of the eye of the occupant in a compartment space. Based on the position of the eye of the occupant, when the occupant sees a bottom end 121a of a shading part 121 of a sun visor 120 vertically lowered , it is determined whether the angle of elevation is larger than 8.5 degrees or not. When it is determined as affirmed, when the occupant sees the bottom end 121a of the shading part 121 of the sun visor 120 vertically lowered, the position of the seat 110 is adjusted in a manner that the angle of elevation becomes 8.5 degrees.