A plug-in circuit breaker with an operating button that includes a button inner end inserted inside the circuit breaker and a button outer end. An indicator slot is arranged inside the operating button, an indicating hole is arranged on the button outer end. The plug-in circuit breaker further includes an indicating member slidably inserted inside the indicator slot and one end of which is provided with a make-contact indicating surface and a break-contact indicating surface. When the plug-in circuit breaker is in a break-contact state, the break-contact indicating surface is arranged opposite to the indicating hole, thus during pressing the operating button, the indicating member moves inside the indicator slot. After the make-contact state, the make-contact indicating surface is arranged opposite to the indicating hole. The indicating member is arranged inside the operating button to save space and to indicate the break-contact and make-contact state through the indicating hole.