Abstract: A toothbrush includes a handgrip portion and a head portion pivoted to the handgrip portion and movable between a folded position and a stretched position. The head portion includes a pair of lugs with a pair of first positioning notches and a pair of second positioning notches which are spaced angularly from the first positioning notches. The handgrip portion includes a pair of parallel plates. A spring-loaded slider provided between the parallel plates and has a projection that extends into the first notches of the head portion when the toothbrush is at the folded position and into the second notches when the toothbrush is at the stretched position. The slider is movable so as to release the projection from the first notches in order to cause the head portion to pivot relative to the handgrip portion to the stretched position due to the provision of a torsional spring which biases normally the head portion away from the handgrip portion.