To provide an eaves trough cutting jig by which a cutting edge cover provided on a motor-driven saw can be smoothly pushed open and which has a constitution capable of surely and sufficiently exposing the cutting edge.

The eaves trough cutting jig 1 is provided with a guide member 2, which is attached to the outer face of an eaves trough 12 to be cut so as to be freely attachable/detachable, and a member 17 to be guided, which is mounted to a base plate 16 of the motor-driven saw 15 provided with the cutting edge 14. The guide member 2 is provided with a guide member body 4, to which a sliding part 3 for sliding the member 17 to be guided is formed, and a pair of guide walls 5 which opposes to each other across the sliding part 3 and is erected toward the outside. The cutting edge cover 24 is provided so as to be freely openable/closable by covering the cutting edge 14 of the motor-driven saw 15. Both end parts 6, 7 of each guide wall 5, with which the end parts 24a on the open side of the cutting edge cover 24 are brought into contact, have an outer face shape suitable for smoothly pushing open the cutting edge cover 24.