The invention discloses a 40 kV indoor high-voltage vacuum circuit breaker which is provided with an operating mechanism (1). The bottom portion of the operating mechanism (1) is arranged on a vehicle body (2); the upper portion of the operating mechanism (1) is provided with a solid-sealed polar pole (3); the side surface of the solid-sealed polar pole (3) is provided with a contact arm (4); one end of the contact arm (4) is connected with a line-outgoing base of the solid-sealed polar pole (3), and the other end thereof is provided with a contact head (5); and a housing of the solid-sealed polar pole (3) is an insulation protection housing (6).