To extend an ion beam pulse of a laser ion source, multiple laser shots could be used. To check the feasibility of this idea, we tested double laser irradiations on an iron target. When the interval of the two laser shots is longer than 10 μs, the obtained ion current profile was expressed as a sum of two individual expanded laser plasmas. However, if the interval is too close, a current reduction was observed. This technique can be effectively applied to low charge state ion production.