An electric field measuring apparatus can guide, with a predetermined optical path length, pulse light with a short pulse width output from a laser light source to an object to be measured or an electric field sensor without expansion of the pulse width caused by wavelength dispersion, thereby enabling electric field measurement with a high time resolution. A laser luminous flux incident on an input end of an input optical system is divided by a light dividing section into probe light and pumping light. After being transmitted through a light delaying device, the probe light is guided through an articulated light guiding patt at reflecting mirror type in which a plurality of tubular light guiding sections, each of which has a light guiding path therewithin inducing substantially no wavelength dispersion with a bending point at which reflecting mirror is disposed, are rotatably cascaded to each other such that their light guiding paths coincide with each other by way of joint sections, so as to be supplied to a microscope unit. On the other hand, the pumping light is guided through an articulated probe light guiding path of reflecting mirror type so as to irradiate an object to be measured. Also, a CCD camera is coupled to the exit end of an articulated reflecting mirror type light guiding path, allowing the positioning of the point irradiated with the pumping light.