A continuous cap feed mechanism for use with fastener driving device includes a housing for receiving a coiled strip of interconnected caps removably mounted the fastener driving device. The housing includes a passageway for guiding the strip of caps from the coil to a position beneath a fastener to be driven by the fastener driving device and an advancing mechanism for moving the leading cap on said strip from the passage to the position beneath the fastener to be driven after the fastener driving device drives a prior fastener into a cap and as it is moved away from the previously driven fastener. The advancing mechanism includes a driver movably mounted in the housing for movement between an extended and retracted position adjacent the location on the fastener driving device at which the fastener driving device drives fasteners. The driver is moved from its extended to its retracted position as it engages a work piece to which a cap is to be fastened is biased towards its extended position and includes a pusher mechanism for engaging a cap in the strip in the housing and urging the strip in the passageway towards the fastener driving device as the driver returns to its extended position when the housing is moved away from the work piece.