To provide a connection structure of very easy connection operation for a watch case to a band and a band piece to another, of beautiful appearance because of a surface decoration part, providing formation which will not be broken when not carried, having a fitting function to an arm when carried, and without direct contact between the watch case and band, or between the band pieces to prevent contact flaws.

Engagement grooves 1b to communicate with opening parts 1a opened in lengthwise end surfaces of a watch case 1 and a band piece are provided, and a connection member 3 comprising plastic material integrally having a connection rod 3a and engagement protrusions 3b to be engaged with the opening parts 1a and the engagement grooves 1b in the watch case 1 and the band pieces is provided. A recessed lock part 1c is formed in each engagement groove 1b in the watch case 1 and the band piece, a protruded stop part 3c to be engaged with the recessed lock part 1c formed in the engagement groove 1b is provided on the connection member 3, and the lock part 1c is engaged with the stop part 3c for connecting the watch case 1 to the band piece by the connection member 3. A decoration part is formed on an upper surface, and foot parts are formed on a lower surface for filling a gap between the band pieces. Flaws are not formed on an end surface, decoration effect is improved, and it fits to an arms because of the elastic foot parts.