A control device as a noise estimation device is applied to a vehicle including an internal combustion engine as a power source and a transmission as a power transmission mechanism. The control device is provided with a storage device that stores mapping data, which is data that defines a mapping learned by machine learning, and a CPU as an execution unit. When variables on an output of the power source and variables indicating a state of the power transmission mechanism are input as input variables, the mapping outputs, as output variables, variables indicating a sensory level of noise caused when rattling sound generated by the operation of the power transmission mechanism is transmitted to a cabin of the vehicle. The CPU estimates the sensory level based on the values of the output variables output from the mapping by inputting the values of the input variables into the mapping.