A gas combustion type driving tool is provided with two modes including: a contact mode in which a contact arm 15 is pressed against a workpiece P into which a nail is to be driven and the nail is driven under a condition that a trigger lever 16 is pulled; and a trigger mode in which the trigger lever 16 is pulled and the nail is driven under a condition that the contact arm 15 is pressed against the workpiece P. In either mode, a nail driving can be continuously executed.