PURPOSE: To facilitate cutting-off of a section capable of redifferentiating a plant from a section of shoot primordium by finely cutting the shoot primordium in a form of lattice.

CONSTITUTION: A conveyer 1 providing a number of projections 4 having rectangular shape when viewed in plan at prescribed intervals in conveying direction and width direction on the surface is rotatably provided and a cutting body 3 having a blade 2 penetrating into a groove 11 between projections 4 is vertically provided so as to enable reciprocating motion above the halfway part in conveying by the conveyer 1 and when a shoot primordium 19 carried by the conveyer 1 reached prescribed cutting position, the conveyer 1 is stopped and the cutting body 3 is lowered and the shoot primordium 19 is finely cut to provide a section of 21 of shoot primordium.