An autosampler for a chromatograph, comprising: a sample injector that executes an operation of injecting a sample into an analysis flow path for chromatography; an information inputter through which a user inputs an injecting condition in regard to the sample injector; and a control device including an electronic circuit on which a CPU (Central Processing Unit) and a data storage device are mounted, said autosampler being characterized in that: the control device includes, as functions obtained by execution of a predetermined program stored in the data storage device by the CPU, a sequence data creator configured to create sequence data in which an operating instruction for causing the sample injector to execute a successive injecting operation of injecting a same sample multiple times is written, and configured to create an initial injection sequence in which an operating instruction for an initial injecting operation of the successive injecting operation is written to save the initial injection sequence in a first data region, create a repetitive injection sequence in which an operating instruction for a repetitive injecting operation to be executed after the initial injecting operation is written to save the repetitive injection sequence in a second data region, and save a duplicate of the repetitive injection sequence in the second data region in a third data region, based on the injecting condition input through the information inputter; a controller that controls the sample injector and is configured to cause the sample injector to execute the successive injecting operation by repeatedly executing the repetitive injection sequence in the second data region until a count of sample injection carried out by the sample injector reaches a set count after the initial injection sequence in the first data region is executed; a sequence changer configured to change the repetitive injection sequence in the third data region based on a changed injecting condition when the changed injecting condition in regard to the repetitive injecting operation is input by the user through the information inputter; and a sequence re-writer configured to rewrite the repetitive injection sequence in the second data region with the repetitive injection sequence in the third data region when the repetitive injection sequence is executed repeatedly. a sample injector that executes an operation of injecting a sample into an analysis flow path for chromatography; an information inputter through which a user inputs an injecting condition in regard to the sample injector; and a control device including an electronic circuit on which a CPU (Central Processing Unit) and a data storage device are mounted, the control device includes, as functions obtained by execution of a predetermined program stored in the data storage device by the CPU, a sequence data creator configured to create sequence data in which an operating instruction for causing the sample injector to execute a successive injecting operation of injecting a same sample multiple times is written, and configured to create an initial injection sequence in which an operating instruction for an initial injecting operation of the successive injecting operation is written to save the initial injection sequence in a first data region, create a repetitive injection sequence in which an operating instruction for a repetitive injecting operation to be executed after the initial injecting operation is written to save the repetitive injection sequence in a second data region, and save a duplicate of the repetitive injection sequence in the second data region in a third data region, based on the injecting condition input through the information inputter; a controller that controls the sample injector and is configured to cause the sample injector to execute the successive injecting operation by repeatedly executing the repetitive injection sequence in the second data region until a count of sample injection carried out by the sample injector reaches a set count after the initial injection sequence in the first data region is executed; a sequence changer configured to change the repetitive injection sequence in the third data region based on a changed injecting condition when the changed injecting condition in regard to the repetitive injecting operation is input by the user through the information inputter; and a sequence re-writer configured to rewrite the repetitive injection sequence in the second data region with the repetitive injection sequence in the third data region when the repetitive injection sequence is executed repeatedly.