A device for determining optimal complex stimuli for tinnitus treatment, the device comprising: a sound stimulus generator configured to generate a sound stimulus; an electrical stimulus generator configured to generate an electrical stimulus; a user input receiver configured to receive a user input; and a controller, wherein the controller is configured to identify one or more sound stimuli selected by the user input received through the user input receiver from among a plurality of sound stimuli, identify one or more electrical stimuli selected by the user input received through the user input receiver from among a plurality of electrical stimuli, determine a first complex stimulus sequence of complex stimuli in which the one or more selected sound stimuli and the one or more selected electrical stimuli are combined, and apply the complex stimuli to the user, wearing a tinnitus treatment device, through the sound stimulus generator and the electrical stimulus generator according to the determined first complex stimulus sequence, wherein the controller is further configured to receive effect diagnosis score information for each complex stimulus sequence through the user input of the user, and determine an optimal complex stimulus sequence from among the plurality of complex stimulus sequences on the basis of the received effect diagnosis score information, the device being characterized in that the effect diagnosis score information for the complex stimulus sequence is determined on the basis of each weight for each of the complex stimuli constituting the complex stimulus sequence, and each weight is determined in consideration of residual suppression effect. a sound stimulus generator configured to generate a sound stimulus; an electrical stimulus generator configured to generate an electrical stimulus; a user input receiver configured to receive a user input; and a controller, wherein the controller is configured to identify one or more sound stimuli selected by the user input received through the user input receiver from among a plurality of sound stimuli, identify one or more electrical stimuli selected by the user input received through the user input receiver from among a plurality of electrical stimuli, determine a first complex stimulus sequence of complex stimuli in which the one or more selected sound stimuli and the one or more selected electrical stimuli are combined, and apply the complex stimuli to the user, wearing a tinnitus treatment device, through the sound stimulus generator and the electrical stimulus generator according to the determined first complex stimulus sequence, wherein the controller is further configured to receive effect diagnosis score information for each complex stimulus sequence through the user input of the user, and determine an optimal complex stimulus sequence from among the plurality of complex stimulus sequences on the basis of the received effect diagnosis score information, the device being characterized in that the effect diagnosis score information for the complex stimulus sequence is determined on the basis of each weight for each of the complex stimuli constituting the complex stimulus sequence, and each weight is determined in consideration of residual suppression effect.