Provided are a communications state determination device, etc., capable of improving the accuracy of network state specification. This communications state estimation device comprises: a setting means that, in accordance with given communications parameters, applies the communications parameters to a communications device that determines the occurrence of communications errors in communications with a communications destination device; a detection means that sends communications instructions to the communications device that performs communications, in accordance with received communications instructions, and detects the occurrence of communications errors that have been determined in the communications that are in accordance with the instructions; and an estimation means that estimates whether or not the communications device can perform the communications, on the basis of the communications parameters and the existence or otherwise of communications errors.