pulling operation but a direction other than the direction of the terminal connector pulling operation namely holder portion 27 can pivotally move about engaging projection 41 d while keeping the sliding engagement with connector mounting arm 41 this allows appropriate positioning of terminal connector 2 relative to mount portion 11 of transmission case 1 even if there is production error of transmission case 1 and control valve unit 4 or there occurs error in assembling control valve unit 4 to transmission case 1 this enhances the mountability of the terminal connector mounting structure further engaging grooves 22 are formed parallel to the imaginary plane substantially perpendicular to the axial direction of body portion 29 of terminal connector 2 namely engaging grooves 22 are substantially perpendicular to the direction of the terminal connector pulling operation in which terminal connector 2 is upward pulled upon being mounted to mount portion 11 upon applying a force to the outer periphery of mount portion 11 of transmission case 1 via grip portion 7 a of tool 7 a reaction force is applied to lift portion 7 c engaged with engaging grooves 22 to thereby upward pull terminal connector 2 thus the positioning of tool 7 can be readily accomplished by the provision of engaging grooves 22 this serves for lightening an operator 39 s labor required for upward pulling terminal connector 2 furthermore since the balanced pulling force can be applied to terminal connector 2 through the.