The invention discloses an inward vision detection device for a circuit breaker, and the device comprises an endoscope probe, a monitor, an image processing apparatus, and a working power supply. The device provided by the invention can stretch into the circuit breaker for video inspection, can find a fault point conveniently and quickly, avoids a disassembly trouble, and greatly improves the efficiency of maintenance and assembly. The invention also discloses a detection technology for the device.