To provide a fitting structure of a maintenance cover of a covered faucet hardly causing a clearance gap of the peripheral edge of an opening of a cover body to which a maintenance cover is fitted and fixed.

This fitting structure 110 of the maintenance cover 70 of the covered faucet 1 including a cover 11 covering the water faucet body 2 includes: a cover body 112; and the maintenance cover 70 removably fitted to the opening 113 of the cover body 112. Collars 49, 50 and the maintenance cover 70 are provided with engagement parts 56, 76 engaged with each other in the fitting direction of the maintenance cover 70, and provided with locking parts 54, 74 locking each other in the expanding direction of the collars 49, 50 in the opening 113.