| 摘要 |
PROBLEM TO BE SOLVED: To provide a toothbrush in which supporting position of the toothbrush may be easily positioned at a rear side in a grip main body part, fatigue is hardly provided in use, excessive brushing pressure can be reduced unconsciously.SOLUTION: A toothbrush 1 of the present invention has a total weight of 5 g or more and 30 g or less, and a full length (L1) of more than 160 mm and 200 mm or less. In the toothbrush 1, when i) an explanatory variable C is a ratio ((L2×100)/L1) of a straight line distance (L2) from a rear end part 3e of the grip main body part 3 to a gravity center G of the toothbrush relative to a full length (L1); ii) an explanatory variable T is a periphery length (S1) at a position P1 apart forward from the rear end part 3e by 90 mm; and iii) an explanatory variable R is a ratio (S1/S2) of the periphery length (S1) at the position P1 relative to the periphery length (S2) at a position P2 apart forward from the rear end part 3e by 20 mm, a handle configuration variable P in the following formula (1) is 150 or more and 350 or less. P=4.57+5.91C+0.515T+154R...(1) |
