1. A bottom sediment determining device for being inputted with an echo signal corresponding to an ultrasonic wave outputted underwater, and determining water bottom sediment using a neural network, the device comprising: a memory for storing two or more parameters to be used in the neural network so as to be associated with positional information; a receiver for receiving the positional information; an acquisition module for acquiring the parameters corresponding to the positional information; and a setting module for setting the parameters to the neural network.