A high speed electronic light shutter consisting of a lithium niobate Pockel cell and a high speed electronic switch is presented. The shutter can be used to switch a continuous laser beam either on or off in less than 40 ns and keep it in the preferred mode for a predetermined period of time ranging from milliseconds to about 10 s. In the electronic switching circuit the short switch-on time is achieved by utilising avalanche transistors. The switch is then held on for a predetermined time by transistors that are controlled by a CMOS dual monostable. The electronic switch has the advantages of being simple and easy to construct.