To provide a wireless LAN automatic site survey device and the like which automates drawing of a two-dimensional electric field distribution.

A position detector 20 detects the two-dimensional position of a dolly 60. An electric field intensity detector 30 detects electric field intensity by using an antenna. A detected data processor 40 correlates the detected position and the electric field intensity and stores as a two-dimensional electric field distribution. A drawing data processor 50 images the stored two-dimensional electric field distribution. With this invention, two-dimensional position of the dolly 60 is detected during running a measurement region with the dolly 60, and the electric field at the position is detected. By correlating the detected position and the electric field intensity, two-dimensional electric field intensity distribution is imaged, and then the drawing of the two-dimensional electric field intensity distribution is easily automated.