This combustion adjustment method applied to the combustion control of a combustor executes a first step for selecting a combustion parameter for a load of a gas turbine and increasing or decreasing a command value of the combustion parameter from an original location. When the command value reaches a target tolerance upper limit value or a target tolerance lower limit value, the first step is terminated. Furthermore, a second step for decreasing or increasing the command value in a direction opposite to that of the first step is executed. When the command value reaches the target tolerance upper limit value or the target tolerance lower limit value, the present invention includes a combustion tolerance confirmation step for confirming a combustion tolerance range of the combustion parameter at which the second step is terminated.