Provided is a technique that can improve a physical sensation of a user during treatment. A low-frequency treatment device according to one aspect of the present invention includes a pad portion configured to be able to supply a low-frequency pulse current to a contact target, and an output unit configured to output, during supply of the low-frequency pulse current by the pad portion, at least one of light and sound synchronized with a change in a supply state of the low-frequency pulse current. For example, the low-frequency treatment device according to one aspect of the present invention includes a control unit configured to perform control of supply of the low-frequency pulse current by the pad portion and control, in conjunction with the control of supply of the low-frequency pulse current, of output of at least one of the light and sound by the output unit.