A simple internal conversion electron spectroscopical method was coupled with RNAA. High energy internal conversion electrons were measured at room temperature using a surface-barrier silicon detector and MCA. By neutron irradiation of Cd and Sn, 1 1 5 Cd and 1 1 3 Sn were produced. Their daughter nuclides, 1 1 5 m In and 1 1 3 m In emit internal conversion electrons of relatively high energy. They were extracted into diethyl-ether from hydrobromic acid solution, back-extracted to water and evaporated to dryness in a stainless steel dish. The dish and silicon detector were placed in a chamber so that they were facing each others. By supplying 200 V of bias to detector, internal conversion electrons peaks of 308.3 and 363.8 keV from 1 1 5 m In and 1 1 3 m In can be observed even at room temperature. The present method can be applied to RNAA such as in the determination of Cd in metallic zinc powders.