To provide a portable cutting tool, which carries out easily a cutting operation maintaining a dust collection ability not only in a horizontal direction and a vertical direction, without limiting an operational direction, and a dust collection structure.

The portable cutting tool 1 includes a dust collection structure 10 having a protective cover body 11 and a dust collection part 14. The dust collection part has a cylindrical body 15 having a rectangular dust collection opening 15c on the one hand and a connection opening 15e connecting a duct collecting hose Sh on the other hand, an auxiliary dust collecting plate 16 having one side auxiliary plate 16A and the other side auxiliary plate 16B arranged respectively at the cylindrical body along the side surface of a rotary blade 9 centering the rectangular dust collection opening, and a connection mechanism 19 of the cylindrical body with the protective cover body. The connection mechanism comprises an installation base 17 provided on the protective cover body, a support 17E attached to the installation base, an engaging member 18 supported by the support and engaging the cylindrical body, and an elastic member 18E locked to the installation base and biasing the engaging member to a member to be cut side.