Cutting instrument (1) of electric type, in particular for pruning branches (60), comprising a grip body (25) at which an user can grip the instrument (1) and a push button (26) to start the rotation of a cutting blade (2) about a rotation axis (102). The cutting blade (2) can rotate about its rotation axis (102) for moving from a distant position to an approached position, or vice-versa, with respect to a fixed counter-blade (3). The cutting blade (2) is connected to the shaft (11) of an electric motor (10) by a mechanical transmission comprising essentially a conical pinion gear (20) and a curved rack (15). The conical pinion gear (20), at a first end (21), has a recess (22) in which a shaft (11) of the motor (10) is inserted. This way, when the motor (10) is operated the conical pinion gear (20) rotates integrally to the shaft (11) about a rotation axis (101). The pinion gear (20), at a second end (23) opposite to first end (21), has a protrusion (24) that is adapted to be put in a recess, or bush, (34) that is made in the mounting body (30).
