PROBLEM TO BE SOLVED: To provide a cover mounting structure of a high-voltage component capable of stably mounting a cover without complicating a configuration.SOLUTION: A high-voltage component comprises a case 2 for accommodating a high-voltage device and a circuit breaker 31 and a cover 5 for closing the case 2, a power supply circuit is disconnected by pulling a service plug 35 out of the circuit breaker 31 and a state where a current can be supplied is obtained by connecting the power supply circuit by loading the service plug 35. The cover 5 includes a service plug insertion hole 7, and in a mounting part 12 within the case 2, a cover presser 20 is provided for pressing a lock part 8 of the cover 5 to the downside. Even when relative displacement is incurred between the cover presser 20 and the cover 5 by dislocation or deformation in the state where the cover 5 is mounted to the case 2, stable fixture of the cover 5 can be maintained.