To develop a simple opener capable of easily exactly opening a screw cap with a relatively large diameter.

Though the opener has such a simple basic structure that a belt is attached to a handle, there are formed at the tip end of the handle two contact points or a tension-giving contact point and a support contact point both contacting the screw cap. The tension-giving contact point acts as the fulcrum of a lever to bind and integrate the screw cap and the handle into one body when the belt wound around the screw cap is strongly pulled. The support contact point acts as a support to prevent the handle from tilting and transmit converting force by a principle of a lever to the screw cap with a frictional force. The belt tension and the converting force of the lever enable a person to open the screw cap by only giving light force to the handle.