Abstract
This thesis deals with risks of violation of judicial impartiality as a consequence of judge's evidence activity, specifically resulting from factual replacing of prosecutor's activities and from substituting of his procedural obligations. At first general factors that can call judge's impartiality into question are described.
Follows the description of reasons for exclusion of judge from carrying out acts of criminal proceedings pursuant to section 30 subsection 1 of the Code of Criminal Procedure. Afterwords is provided comparison of impartiality of judge and prosecutor according to their legal status.
In the next part follows the analysis of particular risks emerging from court's evidential activity, including their reasons and projection of this issue in Czech case law and European Court of Human Rights case law. At the end is described the way how courts adjudicate on prejudice of judge resulting from his excessive evidence activity and mentioned de lege ferenda suggestions.