a molding machine having a first mold and a second mold for injection molding, wherein a molding material is injected into a space between the first mold and the second mold to form a product;

a counting device configured on a side surface of the first mold of the molding machine to obtain a count value of a number of injection moldings of the product formed by the molding machine; and

a management device comprising a memory and a processor,

the processor being configured to execute a calculation process of calculating one or more index values by using a first value and one or more second values, the first value being the count value acquired from the counting device, the one or more second values being reference values that are stored in the memory and are used for determining a next maintenance time, the one or more index values being able to be used for determining the next maintenance time, and

the processor is configured to further execute an output process of outputting parameters, which are obtained from the count values in a first period and a second period, in a time-series manner in which starting points of the first period and the second period are made to coincide each other,

wherein the first period is a period from a last maintenance time, and

wherein the second period is a period from a first maintenance time before the last maintenance time to a second maintenance time next to the first maintenance time.