A portable machining device (1; 50), comprising: a base (2; 52) with which a material to be cut is brought into contact; a machining device main body (10; 51) which is supported above an upper surface of the base (2; 52); and a handle (20; 70) that is formed integrally with the machining device main body (10; 51), wherein: the machining device main body (10; 51) includes a cutting blade (11; 54) that is rotated by an electric motor (12; 60) serving as a drive source, the cutting blade (11; 54) being moved to protrude below a lower surface of the base (2; 52) such that a protruding portion of the cutting blade (11; 54) is cut into the material to be cut for performing a cutting task; an adapter (31; 86) is configured to conduct radio communication with a dust collector (40; 80) or a water injection device of the portable machining device (1; 50), which adapter is removably provided in an interior of the machining device main body (10; 51); characterized in that the adapter (31; 86) is configured to be inserted into an adapter insertion portion (32; 87) which can be covered by a cap (33; 88), wherein after inserting the adapter (31; 86) into the adapter insertion portion (32; 87) and closing the cap (33; 88), the adapter (31; 86) and the adapter insertion portion (32; 87) are shielded in a dustproof configuration; the adapter (31; 86) for conducting radio communication is removed from the machining device main body (10; 51) by moving the adapter (31; 86) in a direction away from the cutting blade (11; 54); and in a state where the adapter (31; 86) is attached and when conducting radio communication between the portable machining device (1; 50) and the dust collector (40; 80) or the water injection device, the dust collector (40; 80) or the water injection device is started and stopped in a manner such that it operates synchronously with a start and stop operation of the portable machining device (1; 50). a base (2; 52) with which a material to be cut is brought into contact; a machining device main body (10; 51) which is supported above an upper surface of the base (2; 52); and a handle (20; 70) that is formed integrally with the machining device main body (10; 51), wherein: the machining device main body (10; 51) includes a cutting blade (11; 54) that is rotated by an electric motor (12; 60) serving as a drive source, the cutting blade (11; 54) being moved to protrude below a lower surface of the base (2; 52) such that a protruding portion of the cutting blade (11; 54) is cut into the material to be cut for performing a cutting task; an adapter (31; 86) is configured to conduct radio communication with a dust collector (40; 80) or a water injection device of the portable machining device (1; 50), which adapter is removably provided in an interior of the machining device main body (10; 51); characterized in that the adapter (31; 86) is configured to be inserted into an adapter insertion portion (32; 87) which can be covered by a cap (33; 88), wherein after inserting the adapter (31; 86) into the adapter insertion portion (32; 87) and closing the cap (33; 88), the adapter (31; 86) and the adapter insertion portion (32; 87) are shielded in a dustproof configuration; the adapter (31; 86) for conducting radio communication is removed from the machining device main body (10; 51) by moving the adapter (31; 86) in a direction away from the cutting blade (11; 54); and in a state where the adapter (31; 86) is attached and when conducting radio communication between the portable machining device (1; 50) and the dust collector (40; 80) or the water injection device, the dust collector (40; 80) or the water injection device is started and stopped in a manner such that it operates synchronously with a start and stop operation of the portable machining device (1; 50). the machining device main body (10; 51) includes a cutting blade (11; 54) that is rotated by an electric motor (12; 60) serving as a drive source, the cutting blade (11; 54) being moved to protrude below a lower surface of the base (2; 52) such that a protruding portion of the cutting blade (11; 54) is cut into the material to be cut for performing a cutting task; an adapter (31; 86) is configured to conduct radio communication with a dust collector (40; 80) or a water injection device of the portable machining device (1; 50), which adapter is removably provided in an interior of the machining device main body (10; 51); characterized in that the adapter (31; 86) is configured to be inserted into an adapter insertion portion (32; 87) which can be covered by a cap (33; 88), wherein after inserting the adapter (31; 86) into the adapter insertion portion (32; 87) and closing the cap (33; 88), the adapter (31; 86) and the adapter insertion portion (32; 87) are shielded in a dustproof configuration; the adapter (31; 86) for conducting radio communication is removed from the machining device main body (10; 51) by moving the adapter (31; 86) in a direction away from the cutting blade (11; 54); and in a state where the adapter (31; 86) is attached and when conducting radio communication between the portable machining device (1; 50) and the dust collector (40; 80) or the water injection device, the dust collector (40; 80) or the water injection device is started and stopped in a manner such that it operates synchronously with a start and stop operation of the portable machining device (1; 50).