A mowing apparatus including: a motive power source; a circular rotational member which is adapted for rotation by the motive power source; at least one flexible cutting line having opposite ends and being adapted to setting on the rotational member in such a manner that the opposite ends of the cutting line freely extends from the rotational member to the outside and rotates with the rotational member, thereby mowing with the ends of the cutting line; and a retention member provided on the rotational member for removably retaining the cutting line on the rotational member, and having at least a pair of first and second faces each of which stands on the rotational member and faces to each other with a space therebetween in which the cutting line is to be received for retention so that the cutting line passes between the first and second faces. For restraining the cutting line from being released from the space, the first and second faces are inclined to each other so that the space between the first and second faces is narrowed according to the farness from the rotational member. Alternatively, the a bend face extends from the first face over the space between the first and second faces.