To provide an obstacle detection notice method of invasion monitoring and an invasion monitoring notice system, which immediately detect/notify various tricks and obstruction through the use of a camera and an auxiliary sensor and which select and takes a means against the tracks and the obstruction.

A television camera 2 which image-picks up an invader, an auxiliary illumination 4 such as infrared LED, an auxiliary sensor means 3 such as a photosensor detecting the brightness of a monitored environment, and an invasion monitoring notice device 1 having an obstruction detection means 10 such as an image sensor and a photosensor and the obstruction notice means 20 of an informing sound means such as a ceramic buzzer or an information display means such as LED are installed.