An engine start device having a first start mode in which the engine is started on a spot by executing a start operation of the engine, and a second start mode in which a necessary accumulated force is previously accumulated in to start in one time in an optional place at an optional timing. In the first start mode, an accumulated force, accumulated by a rotation of a rotation drive section allows the engine to be started on the spot. If switched to the second start mode, the rotation of the rotation drive section is exclusively accumulated and released in the optional place at a desired time so as to start the engine in accordance with a one-touch operation.