The present invention relates to a vacuum switch tube, which includes a first conductive rod and a second conductive rod. A first contact is disposed at the first conductive rod. A second contact is disposed at the second conductive rod. The first contact and the second contact include conductive members and magnetic members, and are sealed in a vacuum tube body and correspondingly disposed. A front end of the first contact is disposed with a convex hemisphere. A front end of the second contact is disposed with a concave hemisphere matching with the front end of the first contact in shape. Therefore, the vacuum switch tube increases surface areas of the contacts, and reduces a resistance increase caused by the poor contacting effect. Meanwhile, a rotating magnetic field is formed between the convex hemisphere and concave hemisphere contacts, thereby facilitating arc-extinguishing and enhancing a breaking capability.