A reciprocating-type cutting blade device (1) has first and second driving bodies (15, 16) driven reciprocatingly in opposite directions. First and second cutting blade bodies (13, 14) are driven reciprocatingly by detachably engaging the first and second driving bodies (15, 16). Two detachable guide plates (11, 12) slidably hold these driving and cutting blade bodies. A first boundary (Q1) is formed between engaging portions (31, 33) of the first cutting blade body (13) and the first driving body (15), and a second boundary (Q2) is formed between engaging portions (32, 34) of the second cutting blade body (14) and the second driving body (16). The boundaries intersect only at points in a planar view, and the engaging portions (31-34) of the cutting blade bodies (13, 14) and the driving bodies (15, 16) maintain this state of intersection over a whole stroke of reciprocating motion.