A hot-dip plating apparatus for plating a thin molten solder film, comprising: a solder bath for, in an inactive atmosphere, accommodating the molten solder to coat with the solder by dipping the base material; a cover section for covering the upper portion of said solder bath and having an inlet port for the base material toward said solder bath and an outlet port from said solder bath; a bearing member provided in a unified manner with said cover section at the solder bath side of said cover section and supporting a shaft of a roller so as to turn around said base material to convey it from the inlet port of said cover section to the side of said solder bath and further convey it to the outlet port from the side of said solder bath; a longitudinal member provided at a side of facing said bearing member with respect to said cover member and being able to slide said cover section and said bearing member in a unified manner; a first conveying section provided at an upper stream side of said solder bath for applying a predetermined tension to the base material that is to be conveyed to said solder bath under a condition of determining an inlet side of the base material as the upper stream side and an outlet side of the base material as a downstream side; a second conveying section provided at the downstream side of said solder bath for conveying the tension applied base material while drawing up the base material from said solder bath at a predetermined speed; a blower section for blowing hot gas on the base material immediately after being drawn up from said solder bath by said second conveying section; and a control section for controlling the blower section to blow the hot gas with a predetermined flow volume and a temperature set to be equal to or higher than a melting temperature corresponding to the composition of the molten solder to trim the molten solder from the base material so as to control the film thickness coated on the base material. a solder bath for, in an inactive atmosphere, accommodating the molten solder to coat with the solder by dipping the base material; a cover section for covering the upper portion of said solder bath and having an inlet port for the base material toward said solder bath and an outlet port from said solder bath; a bearing member provided in a unified manner with said cover section at the solder bath side of said cover section and supporting a shaft of a roller so as to turn around said base material to convey it from the inlet port of said cover section to the side of said solder bath and further convey it to the outlet port from the side of said solder bath; a longitudinal member provided at a side of facing said bearing member with respect to said cover member and being able to slide said cover section and said bearing member in a unified manner; a first conveying section provided at an upper stream side of said solder bath for applying a predetermined tension to the base material that is to be conveyed to said solder bath under a condition of determining an inlet side of the base material as the upper stream side and an outlet side of the base material as a downstream side; a second conveying section provided at the downstream side of said solder bath for conveying the tension applied base material while drawing up the base material from said solder bath at a predetermined speed; a blower section for blowing hot gas on the base material immediately after being drawn up from said solder bath by said second conveying section; and a control section for controlling the blower section to blow the hot gas with a predetermined flow volume and a temperature set to be equal to or higher than a melting temperature corresponding to the composition of the molten solder to trim the molten solder from the base material so as to control the film thickness coated on the base material.