The aim of the study is to determine pre-service and high school physics teachers’ ideas about simple electric circuits. In this study, a test contains eight questions related to simple electric circuits was used to the pre-service physics teachers (32 subjects) graduated from Balıkesir University, Necatibey Faculty of Education, the department of physics education and working as physics teachers (25 subjects) in various High Schools in Turkey to determine their ideas about in the same subjects. As a result, it is found that, in partial, while the physics teachers have alternate conceptions about “sequential reasoning”, “source of stationary current”, and “current usage”, the pre-service of physics teachers have unscientific ideas about “source of stationary current”, “The concept of current, energy and potential differences are used one another by mistaken”, “current usage” and “sequential reasoning”.