PURPOSE: To provide a wood cutting device, with which excellent cutting performance is realized and the operation and management of which are easy and exact, and a wood cutting jig used for the wood cutting device.

CONSTITUTION: In a wood cutting jig concerned, near portal level arms 11, which are arranged separately from each other along the longitudinal direction of a wood 1 so as to be arranged round the wood 1, side plates 12, which connect the level arms 11 with each other at the bases of the respective level arms 11, and a large number of guide holes 13, which are bored on the respective level arms 11. Further, guide bars 14, both the ends 14a of each of which engage with the guide hole 13 of each of the level arm 11 and which can be detachably spanned between the level arms 11 so as to be parallel to the side plates 12, and a plurality of standard pins 15, which are detachably insertingly supported inwards at the proper locations of the side plates 12, are equipped. Especially, the standard pins 15 are arranged at both the longitudinal ends of each side plate 12 and its intermediate part.