It looks like you're using the fei document class which, in turn, builds on the memoir class. The class file fei.cls contains the following instructions:
\renewcommand{\cftchapternumwidth}{4em}
\renewcommand{\cftsectionnumwidth}{4em}
\renewcommand{\cftsubsectionnumwidth}{4em}
\renewcommand{\cftsubsubsectionnumwidth}{4em}
\renewcommand{\cftparagraphnumwidth}{4em}
Observe that the same width -- 4em -- is set aside for all five sectioning headers, from \chapter to \paragraph. If, instead, you want to set aside just enough space to typeset the number plus a minimalist amount of whitespace, you could run the following instructions in the preamble:
\renewcommand{\cftchapternumwidth}{1.0em}
\renewcommand{\cftsectionnumwidth}{1.75em}
\renewcommand{\cftsubsectionnumwidth}{2.5em}
\renewcommand{\cftsubsubsectionnumwidth}{3.25em}
\renewcommand{\cftparagraphnumwidth}{4em} % no change
\defbibheading{bibliography}[\bibname]{%
\clearpage
\phantomsection
\addcontentsline{toc}{chapter}{\bfseries REFER\^ENCIAS}
\chapter*{REFER\^ENCIAS}
\urlstyle{same}}
The \defbibheading instruction above modifies the one given in the file fei.cls to insert no whitespace before REFER\^ENCIAS is inserted in the toc file.