made that the position or the tilt angle of the tub 11 at the initial state of electric power application corresponds to an angle of more than 0 u00b0 but less than 45 u00b0 simultaneously a determination is also made that the current position of the tub 11 corresponds to the 45 u00b0 tilted position then the worm motor 17 is further driven to rotate the tub 11 in right direction until p 1 achieves an off state and then at on state thereby causing the tilt angle of the tub 11 to be an angle of more than 45 u00b0 but less than 90 u00b0 where the state 34 p 1 on and p 2 on 34 is not detected even after the driving of worm motor 17 for the predetermined time a determination is made that the initial position or the initial tilt angle of the tub 11 corresponds to an angle of more than 45 u00b0 but less than 90 u00b0 simultaneously a determination is also made that the current position of the tub 11 corresponds to an angle of 90 u00b0 n u00b0 finally the fourth case wherein the state 34 p 1 off and p 2 on 34 is detected at the initial state of electric power application will be described the fourth case 34 p 1 off and p 2 on 34 will correspond to one of the following cases 4 a when p 2 is covered by the outward protrusion of the first photoshield portion 23a that is when the tilt.