A treatment device which applies energy to a biological tissue to treat the biological tissue, includes: a first holding surface disposed on a first jaw a second holding surface disposed on a second jaw an energy output portion that is disposed in at least one of the first and second holding surfaces, and outputs the energy to the biological tissue held between the first holding surface and the second holding surface a handle that is supported by an operator an operating body that is disposed in the handle and into which an operation of bringing the first and second jaws close to each other is inputtable and an interlocking mechanism that regulates at least one of a closing time until the first and second jaws reach the closed state from the opened state when one operation is input into the operating body for the handle, and a unit closing amount from the opened state toward the closed state, that interlocks at least one of the first and second jaws with the operating body, and that is interposed between the operating body and the handle.
