A chair, in particular an office chair, comprising a pedestal, a seat support supported thereon, a seat plate supported on said seat support, and a backrest secured on said seat support. Said seat support comprises a rear supporting and guiding unit facing said backrest on which said seat plate is supported, and on which said seat plate is guided obliquely relative to the horizontal line against at least one spring element. Said seat support comprises further a front supporting and guiding unit on which said seat plate is supported, and on which said seat plate is displaceably guided.