A sheet conveying device of an aspect of the invention includes: a conveying path that allows a sheet to be conveyed and includes a first guide face and a second guide face opposing and apart from each other at a predetermined interval; a sheet conveying unit disposed on the conveying path; and a first detecting unit and a second detecting unit arranged opposing each other across the conveying path. Each of the first and second detecting unit includes: an arm member rotatably supported to take a posture where the arm member projected from the guide face to the conveying path and a posture where the arm member is retracted from the conveying path by rotating toward the guide face; and a first sensor that outputs a signal depending on the posture of the arm member.