A sheet feeder includes a controller configured to perform a driving process of supplying a motor with an electric current to rotate a roller, perform a stopping process of stopping supplying the electric current in response to determining that the motor has not rotated before a second sensor detects a sheet, when an accumulated rotational quantity of the roller is less than a threshold, set a retry upper limit to a first value, the accumulated rotational quantity being detected by a first sensor in the driving process performed for a first time, when the accumulated rotational quantity of the roller is equal to or more than the threshold, set the retry upper limit to a second value more than the first value, and repeatedly perform the driving process and the stopping process until a number of retries reaches the retry upper limit or until the second sensor detects the sheet.