To provide an excavation device for excavating ground by vibrating it to sample soil or ground water and which has a simple structure with less noise and is economically low in cost.

The excavation device for the ground is constituted so that a vibrator 2 producing vibration for excavation is provided to a basic body 1; a main shaft 5, located at the center section and supported by a rotational driving device 3 in a rotatable manner, is provided; a casing 10 vibrated by the vibrator 2 is provided in the direction of the shaft of the main shaft 5; a rotatable inner road 11 connected with the main shaft 5 is inserted in the casing 10; the vibrator is connected to the main shaft 5 or the casing 10 to vibrate the casing 10 for forming an excavated hole, the inner road 11 is vibrated and is operated vibratingly; and the soil or the ground water is sampled from a specific stratum to test geological features or the quality of water.