1. A correction value computation device for computing a correction value for a control parameter in a manufacturing process executed on a manufacturing apparatus, comprising: circuitry configured to acquire an index value representing a fluctuation phenomenon in a manufacturing apparatus; acquire an apparatus model representing a relationship between the index value and a process element of an environment in which a manufacturing process is executed; acquire a process model representing a relationship between a performance indicator rating results of executing the manufacturing process and the process element; acquire an output value output from a sensor provided in the manufacturing apparatus; transform the output value into a first fluctuation amount for the process element; transform the index value into a second fluctuation amount for the process element based on the apparatus model; compute a fluctuation amount for the performance indicator from the first and second fluctuation amounts for the process element based on the process model; compute a correction amount for the performance indicator from a control range for the performance indicator and the fluctuation amount for the performance indicator; and convert the correction amount for the performance indicator into a correction amount for each process element based on the process model such that a correction value for a control parameter in a process executed on the manufacturing apparatus is computed from the correction amount converted for each process element.