An apparatus for preventing withdrawing and insertion of a carriage of a circuit breaker is disclosed. When a circuit breaker main body is inserted, an interlocking unit operates by interworking with the carriage withdrawing and inserting preventing apparatus, and while the circuit breaker is being closed, a withdrawal and insertion handle prevents a lead screw from being rotated by the interlocking unit. Thus, when the circuit breaker performs a closing operation, unnecessary withdrawing and inserting operation of the carriage is basically prevented to thus prevent various safety accidents, a contact resistance, a temperature increase, and damage to a device resulting from a breakdown.