A control device for a DC/DC converter, which obtains at least one of an output voltage value, an output current value, an input voltage value, an inductor current value, and a capacitor current value of the DC/DC converter, and transmits a switch on ▪ off instruction signal to a drive circuit, the control device comprising: a feedback controller which generates a first time value for switch-off timing as a feedback control signal from at least one of the output voltage value, the output current value, the input voltage value, the inductor current value, and the capacitor current value of the DC/DC converter, a machine learning controller which generates a second time value for switch-off timing as a feedforward control signal from at least one of the output voltage value, the output current value, the input voltage value, the inductor current value, and the capacitor current value of the DC/DC converter, a difference time calculator which-calculates a difference signal between the first time value from the feedback controller and the second time value from the machine learning controller, and transmits a difference signal to the drive circuit, characterized in that the second time value is a product of a weight of a and a deviation between a target value and an estimated value obtained from learning history at a certain sampling time, or is a biased value which is calculated by adding a bias component to the product, where α = A ▪ f (n,λ), A is a factor, which factor is except for zero, for suppressing a first undershoot or overshoot, f (n,λ) is a damping function, λ is a factor, which factor is a positive constant except for zero, for suppressing a subsequent overshoot or undershoot following after the first undershoot or overshoot, and n is an integer indicating the nth sampling. a feedback controller which generates a first time value for switch-off timing as a feedback control signal from at least one of the output voltage value, the output current value, the input voltage value, the inductor current value, and the capacitor current value of the DC/DC converter, a machine learning controller which generates a second time value for switch-off timing as a feedforward control signal from at least one of the output voltage value, the output current value, the input voltage value, the inductor current value, and the capacitor current value of the DC/DC converter, a difference time calculator which-calculates a difference signal between the first time value from the feedback controller and the second time value from the machine learning controller, and transmits a difference signal to the drive circuit, characterized in that the second time value is a product of a weight of a and a deviation between a target value and an estimated value obtained from learning history at a certain sampling time, or is a biased value which is calculated by adding a bias component to the product, where α = A ▪ f (n,λ), A is a factor, which factor is except for zero, for suppressing a first undershoot or overshoot, f (n,λ) is a damping function, λ is a factor, which factor is a positive constant except for zero, for suppressing a subsequent overshoot or undershoot following after the first undershoot or overshoot, and n is an integer indicating the nth sampling.