The present invention provides a coating agent that has excellent durability and a medical instrument (for example, a needle) that has been coated with the coating agent. The coating agent of the present invention includes a condensate (1) of a compound (1-1) represented by the following general formula (1-1) with a compound (1-2) represented by the following general formula (1-2), a polydiorganosiloxane (2), and an amino-group-containing polyorganosiloxane (3). The content ratio of the polydiorganosiloxane (2) is 30 to 75 mass%, based on the total mass of the condensate (1), the polydiorganosiloxane (2), and the amino-group-containing polyorganosiloxane (3).
