A circuit breaker, comprising a circuit breaker housing, and a button mechanism and an operating mechanism connected with said button mechanism, which are arranged inside said circuit breaker housing respectively; wherein said circuit breaker housing includes a switch-on button hole and a switch-off button hole all arranged thereon, said button mechanism includes a switch-on button and a switch-off button slidably arranged inside said circuit breaker housing, respectively, said switch-on button includes a switch-on button operating end arranged at one end thereof and slidably arranged in said switch-on button hole, said switch-off button includes a switch-off button operating end arranged at one end thereof and slidably arranged in said switch-off button hole; whereby while said switch-on button operating end is being pressed toward the inside of said circuit breaker housing to drive said operating mechanism to enable the circuit breaker to switch on, said switch-off button operating end moves toward the outside of said circuit breaker housing, while said switch-off button operating end is being pressed toward the inside of said circuit breaker housing to drive said operating mechanism to enable the circuit breaker to switch off, said switch-on button operating end moves toward the outside of said circuit breaker housing; said operating mechanism includes a bar linkage, and a transmission member and a lever mechanism all pivotally arranged inside said circuit breaker housing, said bar linkage includes a switch-on connecting rod, characterised by said operating mechanism further including a switch-off connecting rod and a transmission connecting rod; the reverse end of said switch-on button is drivingly connected to said transmission member through said switch-on connecting rod, the reverse end of said switch-off button is drivingly connected to said transmission member through said switch-off connecting rod, said transmission member is drivingly connected with the lever mechanism through said transmission connecting rod, and said lever mechanism is connected with a movable contact of the circuit breaker; when said switch-on button is pressed toward the inside of said circuit breaker housing to enable the circuit breaker to switch on, said switch-on button actuates said transmission member to rotate in a first direction through said switch-on connecting rod, meanwhile, the rotation of said transmission member drives said switch-off button to move toward the outside of said circuit breaker housing through said switch-off connecting rod; when said switch-off button is pressed toward the inside of said circuit breaker housing to enable the circuit breaker to switch off, said switch-off button actuates said transmission member to rotate in a second direction through said switch-off connecting rod, meanwhile, said rotation of said transmission member drives said switch-on button to move toward the outside of said circuit breaker housing through said switch-on connecting rod, said first direction and said second direction are opposite to each other. whereby while said switch-on button operating end is being pressed toward the inside of said circuit breaker housing to drive said operating mechanism to enable the circuit breaker to switch on, said switch-off button operating end moves toward the outside of said circuit breaker housing, while said switch-off button operating end is being pressed toward the inside of said circuit breaker housing to drive said operating mechanism to enable the circuit breaker to switch off, said switch-on button operating end moves toward the outside of said circuit breaker housing; said operating mechanism includes a bar linkage, and a transmission member and a lever mechanism all pivotally arranged inside said circuit breaker housing, said bar linkage includes a switch-on connecting rod, characterised by said operating mechanism further including a switch-off connecting rod and a transmission connecting rod; the reverse end of said switch-on button is drivingly connected to said transmission member through said switch-on connecting rod, the reverse end of said switch-off button is drivingly connected to said transmission member through said switch-off connecting rod, said transmission member is drivingly connected with the lever mechanism through said transmission connecting rod, and said lever mechanism is connected with a movable contact of the circuit breaker; when said switch-on button is pressed toward the inside of said circuit breaker housing to enable the circuit breaker to switch on, said switch-on button actuates said transmission member to rotate in a first direction through said switch-on connecting rod, meanwhile, the rotation of said transmission member drives said switch-off button to move toward the outside of said circuit breaker housing through said switch-off connecting rod; when said switch-off button is pressed toward the inside of said circuit breaker housing to enable the circuit breaker to switch off, said switch-off button actuates said transmission member to rotate in a second direction through said switch-off connecting rod, meanwhile, said rotation of said transmission member drives said switch-on button to move toward the outside of said circuit breaker housing through said switch-on connecting rod, said first direction and said second direction are opposite to each other.