A sheet conveying apparatus according to the invention includes a first conveying path; a sheet reverse conveying portion; a second conveying path; a third conveying path; and a movable guide portion configured to guide the conveyed sheet. The guide portion is moved to a position where the sheet can pass when the sheet is guided from the first conveying path to the second conveying path, and the guide portion is moved to a position where the guide portion guides the sheet to the third conveying path while blocking between the first and second conveying paths such that the sheet can not intrude from the second conveying path into the first conveying path when the sheet conveyed by the sheet reverse conveying portion is conveyed in the second direction.