I finally get it:
I've used resizeColumnsToContents()
and resizeRowsToContents()
to make the columns/rows of the table adjust to the data - text, but that doesn't do the same thing with the Table itself - table height and width stays the same. So in order to make table to be sized around the rows and columns I've used this:
self.table.resizeRowsToContents()
self.table.resizeColumnsToContents()
self.table.setFixedSize(self.table.horizontalHeader().length(), self.table.verticalHeader().length())
and now I can scroll with QScrollArea's scrollbars through entire table.