Toothbrush

A toothbrush comprising:

• a head portion provided on a tip end side in a long axis direction and having a bristle tufting surface;
• a grip portion disposed on a rear end side from the head portion;
• and
• a neck portion disposed between the bristle tufting surface and the grip portion,
• wherein a sensing portion for sensing that an external force in a first direction orthogonal to the bristle tufting surface exceeds a predetermined value is provided on a rear end side from the bristle tufting surface,
• the sensing portion
• changes a relationship between a displacement amount of the head portion when a load is applied to the head portion in the first direction toward a back surface side opposite to the bristle tufting surface and a repulsive force generated according to the displacement amount from an increase to a decrease in the repulsive force at a first threshold value according to an increase in the displacement amount, and
• stops the decrease in the repulsive force at a second threshold value where the displacement amount is larger than the first threshold value, and
• when the repulsive force when the displacement amount is at the first threshold value is A, and the repulsive force when the displacement amount is at the second threshold value is B,
• a value represented by B/A is 0.3 or more and 0.9 or less.