To provide a removing method of a core in a casting, by which the core sand in the casting can efficiently be removed at a low cost, and a device therefor.

This method is executed by executing the repeating movement combining one of or plural ways of a linear or a rotating or a swinging movement to a work holding member 3 to apply the repeating vibration to the work and also, applying the hitting vibration to the work with a hitting mechanism 9 fitted to the work holding member 3. This device arranges the repeating movement mechanism 1 for applying the repeating vibration to the work by executing the repeating movement combining one of or plural ways of the linear or the rotating or the swinging movement in the work holding member 3 and also, the hitting mechanism 9 applying the hitting vibration to the work in the work holding member 3.