Reciprocating motion of cutting blade bodies is smoothed while adequately ensuring maintainability.A reciprocating-type cutting blade device 1 of the present invention has first and second driving bodies 15 and 16 which are reciprocatingly driven in opposite directions first and second cutting blade bodies 13 and 14 which are integrally reciprocatingly driven by detachably engaging with the first and second driving bodies 15 and 16 and a pair of detachable guide plates 11 and 12 which hold these driving and cutting blade bodies slidably. A first boundary Q1, which is formed between engaging portions 31 and 33 of the first cutting blade body 13 and the first driving body 15, and a second boundary Q2, which is formed between engaging portions 32 and 34 of the second cutting blade body 14 and the second driving body 16, intersect one another only at points in a planar view, and the engaging portions 31 to 34 of the cutting blade bodies 13 and 14 and the driving bodies 15 and 16 are formed so that this state of intersection is maintained over a whole stroke of reciprocating motion.
