To prevent an erroneous operation and improve operability, a button device and a timepiece including the button device are provided. The button device includes: a cylindrical first guide protector 11 protruding from the lateral face of a wristwatch case 1; and a first button 12 disposed in the first guide protector 11 to be slidable inward and outward of the wristwatch case 1. The first button 12 includes a first button head 13 disposed in the first guide protector 11, and a first button shaft 15 passing through a first through hole 14 of the wristwatch case 1. The first button head 13 is inclined obliquely upward relative to the lateral face of the wristwatch case 1. The first guide protector 11 protects the outer periphery of the first button head 13, and this prevents accidental and erroneous operation of the first button 12. The first button head 13 is inclined obliquely upward relative to the lateral face of the wristwatch case 1, and this allows the user to easily place a fingertip on the outer end face of the first button head 13, and so improves the operability of the first button 12.