To provide a sheet conveyer that moves a conveyance guide to open a sheet conveyance path when an outer cover openably/closably provided in a machine body, thereby enabling a hand to be easily inserted in the machine body, while releasing a nip of a pair of conveyance rollers near the conveyance guide, thereby improving paper jam handleability.

A sheet conveyer includes: a conveyance guide 62 turnably disposed in an outer cover 50; a resist roller 27 rotatably provided in the transfer guide 62 and driven opposite a resist roller 26; and a resist biasing spring 3 for biasing the resist roller 27 relative to the resist roller 26. When the resist roller 27 moves in a direction crossing a direction in which the resist biasing spring 3 biases the resist roller 26, along with opening/closing operation of the outer cover 50 relative to the body of an image forming device 100, the resist roller 27 is brought into pressure contact with or separates from the resist roller 26.