An operation state simulation apparatus for simulating an operation state of a heat pump type hot-water supply system which supplies hot water by using a heat pump, comprising: - a condition input part configured to input a simulation condition for simulating the heat pump type hot-water supply system; - a simulation execution part configured to execute a calculation program which has been set in advance, based on the simulation condition having been input in the condition input part, so as to generate simulation result information which includes an operation state of the heat pump type hot-water supply system and an insufficient quantity of heat in the operation state; and - an output part configured to output the simulation result information generated by the simulation execution part, - wherein the simulation execution part generates the simulation result information including an amount of carbon dioxide emission emitted by the heat pump type hot-water supply system, - wherein the condition input part inputs a plurality of the simulation conditions, and - wherein the simulation execution part generates the simulation result information for each of the plurality of the simulation conditions, - characterized in that the plurality of the simulation conditions to be input into the condition input part include an allowable value of insufficient quantity of heat which is allowed for the heat pump type hot-water supply system, and - wherein the output part outputs only the simulation result information in which the insufficient quantity of heat calculated by executing the calculation program is within a range of the allowable value of insufficient quantity of heat included in the simulation condition corresponding to the simulation result information including a calculated insufficient quantity of heat. - a condition input part configured to input a simulation condition for simulating the heat pump type hot-water supply system; - a simulation execution part configured to execute a calculation program which has been set in advance, based on the simulation condition having been input in the condition input part, so as to generate simulation result information which includes an operation state of the heat pump type hot-water supply system and an insufficient quantity of heat in the operation state; and - an output part configured to output the simulation result information generated by the simulation execution part, - wherein the simulation execution part generates the simulation result information including an amount of carbon dioxide emission emitted by the heat pump type hot-water supply system, - wherein the condition input part inputs a plurality of the simulation conditions, and - wherein the simulation execution part generates the simulation result information for each of the plurality of the simulation conditions, - characterized in that the plurality of the simulation conditions to be input into the condition input part include an allowable value of insufficient quantity of heat which is allowed for the heat pump type hot-water supply system, and - wherein the output part outputs only the simulation result information in which the insufficient quantity of heat calculated by executing the calculation program is within a range of the allowable value of insufficient quantity of heat included in the simulation condition corresponding to the simulation result information including a calculated insufficient quantity of heat.