A driving tool having a trigger, such that after the trigger is on-operated, a contact restriction member starts to rotate to a lock side while rotation resistance is applied thereto by a rotation resistance applying member. A lock portion enters a lock receiving portion to prohibit an on-operation of a contact arm after a reference time has passed after the on-operation of the trigger. As a result, an inadvertent driving operation can be prevented. A mechanical timer mechanism allows for a timer control to be effected under an environment where electric power cannot be supplied.