A blade mounting device of a cutting tool includes a lock device and a blade guide. The lock device is configured to releasably lock a blade against a rod of a cutting tool. The blade guide is movable relative to the rod in an axial direction of the rod and is coupled to the lock device, so that the lock device locks and releases the blade in response to position of the blade guide in the axial direction. The blade guide has a guide recess having a bottom and capable of guiding and engaging the blade, so that the blade guide can be moved by the blade in the axial direction through engagement of the guide recess with the blade. The blade guide has a configuration other than a thin flat plate configuration.