To provide a head cap unit for a bicycle capable of installing an electric member on a steering tube of a fork for the bicycle.
This head cap unit is basically furnished with a cap part 61 and a housing part 62. The cap part 61 is constituted to block an opening upper part of a steering tube 46 of the fork 18 for the bicycle. The housing part 62 is connected to the cap part 61. The housing part 62 forms an electric member storage space in the steering tube 46 when the cap part 61 blocks the opening upper part of the steering tube 46 of the fork 18 for the bicycle.