An image recording apparatus including: a main frame including (a) a pair of side plates facing each other in one direction and (b) a base plate whose opposite end portions in the one direction are respectively supported by the pair of side plates; a guide member provided at an inside area interposed between a pair of side plates in the one direction, so as to define a conveying path through which a recording medium is conveyed; and a sensor device supported by one of the pair of side plates and configured to sense the recording medium conveyed through the conveying path.