A wearable action assisting device comprising: a drive source configured to give power to a wearer; a first detection unit configured to detect a biological potential signal along with a muscle activity of the wearer; and a second detection unit configured to detect an angle of a joint of the wearer; characterized by further comprising: a first control unit configured to perform a signal processing including a filter processing and amplification on the biological potential signal, and to generate a first instruction signal for generating power depending on the biological potential signal after the signal processing on the drive source; a first storage unit configured to store reference parameters of joint angles of the wearer corresponding to a phase configuring a task classifying an action pattern of the wearer therein; a second control unit configured to compare a joint angle detected by the second detection unit with the reference parameters thereby to specify a phase of the action pattern of the wearer, and to generate a second instruction signal for generating power depending on the phase on the drive source; a combination unit configured to combine the first instruction signal and the second instruction signal thereby to generate a combined instruction signal; a generation unit configured to generate a drive current based on the combined instruction signal and supply it to the drive source; a display unit having a screen displaying thereon a first coordinate axis corresponding to a strength of power given to the wearer by the drive source or a response speed of a change in power given to the wearer relative to a change in the biological potential signal; an input unit configured to input an arbitrary designated position in the screen; a third detection unit configured to detect the coordinate of the designated position; a second storage unit configured to store parameter tables defining a correspondence between a coordinate in the screen and parameters of the signal processing in the first control unit; and a setting unit configured to extract parameters corresponding to the detected coordinate from the parameter table and set the extracted parameters in the first control unit. a drive source configured to give power to a wearer; a first detection unit configured to detect a biological potential signal along with a muscle activity of the wearer; and a second detection unit configured to detect an angle of a joint of the wearer; a first control unit configured to perform a signal processing including a filter processing and amplification on the biological potential signal, and to generate a first instruction signal for generating power depending on the biological potential signal after the signal processing on the drive source; a first storage unit configured to store reference parameters of joint angles of the wearer corresponding to a phase configuring a task classifying an action pattern of the wearer therein; a second control unit configured to compare a joint angle detected by the second detection unit with the reference parameters thereby to specify a phase of the action pattern of the wearer, and to generate a second instruction signal for generating power depending on the phase on the drive source; a combination unit configured to combine the first instruction signal and the second instruction signal thereby to generate a combined instruction signal; a generation unit configured to generate a drive current based on the combined instruction signal and supply it to the drive source; a display unit having a screen displaying thereon a first coordinate axis corresponding to a strength of power given to the wearer by the drive source or a response speed of a change in power given to the wearer relative to a change in the biological potential signal; an input unit configured to input an arbitrary designated position in the screen; a third detection unit configured to detect the coordinate of the designated position; a second storage unit configured to store parameter tables defining a correspondence between a coordinate in the screen and parameters of the signal processing in the first control unit; and a setting unit configured to extract parameters corresponding to the detected coordinate from the parameter table and set the extracted parameters in the first control unit.